Tibet History

The Tubo Dynasty was a Tibetan imperial monarchy in the history of the Tibetan ethnic group.

• It was established in the 7^th century by Songtsen Gampo (some scholars consider the 7^th century as the beginning of the Tubo Dynasty). He established his capital in Lhasa and married the Tang Dynasty's Princess Wencheng, thus unifying the Qinghai-Tibet Plateau, creating the Tibetan script, and established a system of officials and laws.


• During the reign of Mangsong Mangzan, the Tubo Dynasty conquered the Tuyuhun Kingdom and expanded into the Tarim Basin.


• During the reign of Tridu Songtsen, the Tubo Dynasty brought the Kingdom of Nanzhao under its submission


• During the reign of Trisong Detsen, Buddhism was made as the state religion, and the first Buddhist monastery in Tibet, Samye Monastery, was founded. The Tubo Dynasty also attacked and plundered the Tang Dynasty's capital, Chang'an(Nowadays, Xian City of Shan‘xi Province).


• King Tride Tsuktsen married the Princess Jin Cheng of the Tang Dynasty.


• In 842 AD, after the ruler Langdarma was assassinated, the Tubo Dynasty experienced a period of internal strife and fragmentation.

During its peak, the Tubo Dynasty's influence extended westward beyond the Pamir Plateau into Central Asia, northward to the entire Southern Route of the Tian Shan Mountains (including the Tarim Basin) and parts of the Northern Route of the Tian Shan, eastward to control the Hexi Corridor and the central part of present-day Shaanxi, and in the southeast, it brought the Nanzhao Kingdom under its suzerainty. It also maintained a border with India along the Ganges River and governed areas south of it.

• Approximately around 2500 BCE, the Zhang Zhung Tribe Kingdom was established as the birthplace of Bon religion and had its unique Xiangxiong script.


• Around 200 BCE, two ancient tribes, the "Congziqiang Tribe" (also known as the Tangmao Tribe) and the "Faqiang Tribe," emerged separately in the southern part of the Tianshan Mountains and in the Cangbei area around the Pamir Plateau, as well as in the Yalong River Valley in the Shannan Area


• Around 127 BCE, according to Tibetan legends, several Bon leaders in the Yarlung Tsangpo River basin jointly enthroned Nyatri Tsenpo (gNya'-khri bTsan-po) as their king. This was the predecessor of the Tubo Kingdom, and later the founder of the Tubo Kingdom claimed to be a descendant of Nyatri Tsenpo.


• In 101 CE, a branch tribe of the Congziqiang Tribe was defeated by the Eastern Han Dynasty army. With less than a thousand survivors, they continued westward and established the Tangmao Kingdom in the area around present-day Lhasa.


• In the mid-4^th century CE, during the reign of King Lhathothori Nyentsen, Buddhism began to emerge in Tibet, including its teachings on the three jewels and rituals of worship.


• Before the 6^th century AD, the entire Tibetan plateau was inhabited by numerous small kingdoms and tribes. They predominantly spoke the Tibetan language, but there were also descendants of Qiang and Xianbei people. These tribes later merged into twelve small states, among which the most powerful was Tubo, located in the Yarlung Valley of the Shannan region.

Note 1: The Three Jewels of Buddhism refer to the Buddha, the Dharma, and the Sangha.
Note 2: The meaning of "Three Reliances of Buddhism" is that the Buddha image is relied upon as the basis of the body, the Buddha's teachings (scriptures) are relied upon as the basis of speech, and the Buddha stupa is relied upon as the basis of the mind.
Note 3: "Worship" or "to offer reverence", refers to religious activities such as paying respect, offering homage, and singing praises.

In the late 6^th century AD, King Namri Songtsen (570-629; reign 618-629) of the Tubo tribal kingdom began using military force to annex neighboring tribes.

In 618 AD, according to legend, Princess Tritsun of the Lichhavi Dynasty (now Nepal) married Songtsen Gampo.

Note: There are different accounts of when Princess Tritsun arrived in Tibet. According to the recorded history of Nepal, her father died in 621 AD, suggesting that she entered Tibet before that year. However, this date is not exact, only a rough estimation. The main sources of information about Princess Tritsun come from Buddhist history books such as "Baxyi", "The Tibetan Royal Chronicle," and "The History of Tibetan Buddhism of Butun." There is no mention of Princess Tritsun in Dunhuang documents, Tubo inscriptions, or Chinese historical books, so scholars like Giuseppe Tucci doubt whether she was a historical figure. Buddhist history books claim that Buddhism was introduced during the time of Songtsen Gampo, but there is no mention of this in Dunhuang documents, leading scholars to suspect that Tubo Dynasty may not have embraced Buddhism until the time of Trisong Detsen in the 8^th century.

In the year 629 AD, after the death of Namri Songtsen, his son Trisongzan (Songtsen Gampo) ascended to the throne. According to the Dunhuang documents P.T.1287VI, Trisongzan's father, Namri Songtsen, was killed by rebels, and prominent figures such as Zhangshung, Supi, Tabo, Gungbu, and Niyangbo openly betrayed him.

In the early years of Trisongzan's reign, there were rebellions everywhere in Tubo Kingdom (Tibet), causing chaos and posing challenges to the newly established Tubo regime. At the age of only thirteen, Trisongzan faced these dangers and ascended to the throne. He swiftly took decisive actions, using force to suppress the rebels and "exterminate them completely, eliminating their future generations." Through these measures, he brought the chaotic situation under control.

To consolidate his absolute royal power and strengthen the relationship between the ruler and his subjects, Trisongzan employed a dual strategy. On one hand, he harshly punished those who committed crimes and offenses, imposing severe penalties. On the other hand, he rewarded and bestowed honors upon his meritorious subjects, extensively utilizing the traditional form of oath-taking to reinforce their loyalty.

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Songtsen Gampo was the founder of the Tibetan Empire, and is traditionally credited with the introduction of Buddhism to Tibet, influenced by his Nepali and Chinese queens, as well as being the unifier of what were previously several Tibetan kingdoms. He is also regarded as responsible for the creation of Tibetan alphabet and therefore the establishment of Classical Tibetan, the language spoken in his region at the time, as the literary language of Tibet.

In the year 632 AD, Trisongzan (Songtsen Gampo) seized the central Tibetan region of Luo-suo (now, Lhasa) from the Tangmao Tribe kingdom, leading to the downfall of the Tangmao Tribe kingdom.

In 633 AD, Trisongzan (Songtsen Gampo) established the capital in Luo-suo (now, Lhasa) and proclaimed the country as "Tubo". The king was called "Tsanpo", and he began constructing a palace on the Red Mountain in the center of Lhasa.

In 634 AD, Trisongzan (Songtsen Gampo) dispatched envoys for the first time to the Tang Dynasty capital of Chang'an (Now, Xi'an, Shaanxi Province). This marked the first diplomatic contact between Tang Dynasty and Tubo Dynasty. At the end of the same year, the Tang Dynasty sent envoy Feng Dexia to accompany the first Tubo Dynasty's envoy back to Tubo, and then visit the Tubo Kingdom. This was the first interaction between the two dynasties

Note: The Tang Dynasty and Tubo Dynasty rose almost simultaneously. When Songtsen Gampo's army ventured out of the treacherous mountains and arrived in the eastern part of the Qinghai-Tibetan Plateau, they encountered the powerful Tang Empire ruled by Emperor Li Shimin. In response, Songtsen Gampo proactively adopted a policy of conciliation.

In 635 AD, Prince Narendradeva of the Licchavi Vansa (now Nepal) sought refuge in Tubo Dynasty after his uncle, King Vrishadeva, usurped the throne.

In 636 AD, Tibet King Songtsen Gampo sent envoys to accompany Tang envoys back to the Tang Dynasty's capital of Chang'an (now Xi'an, Shaanxi Province) and proposed to marry a Tang princess.

In 637 AD, Emperor Taizong of the Tang Dynasty rejected the marriage proposal from Songtsen Gampo, the king of Tubo (Tibet). The Tubo envoy returned and reported this.

In the same year, the "Face War" of Tubo erupted in July. Songtsen Gampo blamed the rejection of the Tubo-Tang marriage proposal on interference from the Tuyuhun Kingdom. As a result, the Tubo Kingdom, in alliance with the Kingdom of Yatong Kingdom (Zhang Zhung), launched an attack on the Tuyuhun Kingdom. Unable to resist Tubo, the Tuyuhun regime fled to the area north of Qinghai Lake, and the vast grassland south of Qinghai Lake became under Tubo's control.

Afterward, the Tubo Kingdom began to advance and attack the nearby Dang-xiang kingdom and Bailan Qiang kingdom, making them submit as vassals. Meanwhile, Tubo mobilized an army of approximately 200,000 soldiers, preparing to attack the Tang Dynasty.

In 638 AD, the Tibetan army, with a force of 200,000 troops, advanced to the southwestern border of the Tang Dynasty - Songzhou (now Songpan County, Sichuan Province), attempting to use force to compel a marriage. At the same time, Tibet sent envoys to the Tang Dynasty to propose marriage again, but they were once again rejected. As a result, Songtsen Gampo decided to launch an attack on Songzhou, leading to the outbreak of the first battle between the Tang Dynasty and Tubo Dynasty known as the “Battle of Songzhou”. The Tang Dynasty defenders in Songzhou were defeated by the Tibetan forces. The Qiang tribal leaders of Kuozhou (north of Songpan County, Sichuan Province) and Nuozhou (north of Songpan County) surrendered to Tubo Army, and other Qiang tribes also surrendered one after another. This drew great attention from the Tang Emperor, Tang Taizong.

Subsequently, the Tang Dynasty dispatched a combined force of 50,000 infantry and cavalry to counter the Tibetans. On the 6^th day of the 9^th month in the lunar calendar, the vanguard of the Tang army launched a surprise attack on the Tibetan camp at night while they were unprepared. Over a thousand Tibetan soldiers were killed or wounded, and Songtsen Gampo's army retreated. According to the book "New Book of Tang - Biography of Tubo," prior to this battle, as Songtsen Gampo had been engaged in continuous military campaigns, several of his ministers requested him to return, but he did not listen and eight of them committed suicide. From then on, Songtsen Gampo's eastward expansion was frustrated, and the Tibetan army withdrew. After the Tibetan army retreated from Songzhou, Songtsen Gampo sent his envoy, the minister Gar·Tongtsan Yulsung (referred to as "Lu Tongtsan" in the historical records of the Tang Dynasty), to offer tribute to the Tang Dynasty and propose marriage once again. This time, Emperor Tang Taizong agreed to Tibet's request and agreed to marry Princess Wencheng to them.

Note: The victory or defeat in the "Battle of Songzhou" is recorded differently in Chinese and Tibetan historical texts, with each side claiming victory.

In 640 AD, Tibet sent Tibetan youths to the Tang Dynasty capital, Chang'an(Now, Xi'an, Shaan'xi Province), to study at the national academy and learn about Tang Dynasty culture.

In October of the same year, Songtsen Gampo sent his prime minister, Lu Tongtsan (also known as "Gar·Tongtsan Yulsung"), as an auspicious and fortunate envoy, bearing abundant gifts of gold and treasures, to visit the Tang Dynasty and represent him in welcoming and marrying Princess Wencheng.

In 641 AD, in the first month, Emperor Tang Taizong of the Tang Dynasty sent his minister to escort Princess Wencheng to Tubo Dynasty. Songtsen Gampo personally led his troops to Bohai (Zhalin Lake in Qinghai) to await the arrival of the princess Wehcheng.

With the distant marriage of Princess Wencheng, various production technologies such as agricultural tools manufacturing, papermaking, textile, brewing, and milling, as well as traditional scientific knowledge such as mathematics and medicine from the Tang Dynasty, gradually spread to Tubo Dynasty. At the same time, Princess Wencheng also brought a large number of silk, gold and silver, scriptures, Buddhist statues, and pagodas to Tubo Dynasty.

Under the influence of Princess Wencheng, Han Chinese Buddhism was introduced to Tibet. Subsequently, Tibet sent noble youths to Chang'an to study and learn about the Central Plains culture. The marriage alliance and cultural exchange opened up a positive channel between Tubo Dynasty and the Tang Dynasty, and for more than a decade, the Tang Dynasty and Tubo Dynasty coexisted harmoniously.

In this year, the Tibetan army escorted Naren Drolma into Nepal, where they killed Vishnu Jiduo and helped Nalendra Drolma regain the throne, making Nepal a vassal state of Tubo Dynasty. Then (there is a saying that it happened in 618 AD), Songtsen Gampo married Princess Bhrikuti Devi of Nepal (also known as Tritsun Princess in Tibetan).

Note: Later Buddhist historians depicted Princess Wencheng as an embodiment of the goddess Tara. They portrayed Songtsen Gampo's marriage to Princess Wencheng as a means to obtain an image of Shakyamuni Buddha and promote Buddhism. The historical accounts about the political nature of the marriage alliance between Tang and Tubo are greatly distorted. The reason why Songtsen Gampo repeatedly proposed marriage to the Tang Dynasty was that by marrying a princess from the Great Tang, it undoubtedly enhanced his prestige and benefited his ongoing unification of the Tibetan plateau. Since the Han Dynasty, the Central Plains dynasties have had the custom of establishing marriage alliances with neighboring ethnic groups, especially with northern tribes. Although the motivations may vary, these alliances serve the purpose of winning hearts and have been an important part of the "Jimi (harmonization) policy" throughout history.

Princess Wencheng was not Emperor Tang Taizong's biological daughter, but the Tibetan historical texts all claim that she was the emperor's daughter, perhaps the Tibetans held the same view. In Chinese historical texts, Princess Wencheng's identity is also unclear, only stating that she was a princess of the imperial family, and allowing her to marry into Tubo seems to be a temporary expediency.

Songtsen Gampo and Princess Wencheng did not live together for a long time. According to "Tibetan Annals," they lived together for three years, which may be due to Songtsen Gampo's frequent military campaigns in Zhang Zhuang and other regions. After Songtsen Gampo's death, Princess Wencheng lived in Tibet as a widow for thirty years, and her life was full of ups and downs. Many legends and stories about Princess Wencheng have been passed down through the ages, and she is universally respected by later generations. Princess Wencheng made significant contributions to the spread of Buddhist culture and the introduction of Central Plains culture to Tibet.

In Tandrue monastery in Tsetang, there is an embroidered Buddha statue, said to have been personally embroidered by Princess Wencheng. Above the Buddha statue, there are depictions of the sun and moon, with a bird in the sun and traces of a toad in the moon, showing rich cultural characteristics of the Tang Dynasty

Jimi (harmonization) policy

Jimi: "Ji" refers to a horse's reins; "mi" refers to a cow's leash. It metaphorically means control and influence. Regions under the implementation of Jimi(harmonization) policy were nominally subordinate to the imperial court but actually ruled by local indigenous leaders. During the Tang Dynasty, the southwestern and northwestern regions adopted the "Jimi (harmonization) policy" towards ethnic minorities, recognizing the local indigenous nobles, granting them titles of princes and dukes, and opening up trade.

In several dynasties including the Song, Yuan, Ming, and Qing Dynasties, the "Jimi (harmonization) policy" was renamed as "Tusi System", "Tusi" was the official title for officials in China's border regions at that time, and it was used to grant titles to ethnic minority tribal leaders in the northwest and southwest regions.

In the year 642 AD, the Zhang Zhung Kingdom was located in the northwest of Tibet, at the northern foot of the Himalayas. Its king, Li Mixia, had married Zanmeng Sadmagar, the sister of Songtsen Gampo, as his queen, and initially, they were in an alliance. However, as the Tibetan Empire grew stronger, their relationship deteriorated. In that year, Songtsen Gampo led an army to attack Zhang Zhung Kingdom, citing the queen's loss of favor.

In 643 AD, Songtsen Gampo's son, Gungtsen Gungzan, who had succeeded him as the emperor, passed away. Songtsen Gampo resumed his position as the emperor.

Note: The exact date of Songtsen Gampo's abdication before his son Gungtsen Gungzan became emperor is unknown.

In 644 AD, the Tibetan army, led by Songtsen Gampo himself, took three years to conquer Zhang Zhung Kingdom and kill its king, Li Mixia. As a result, the Zhang Zhung Kingdom was destroyed, and Songtsen Gampo appointed Kyungpo Pungse as the superintendent of Zhang Zhung Kingdom.

At this time, the territory of the Tubo Empire had expanded to the eastern part of Kashmir, laying the foundation for its future dominance in Central Asia. The Battle of Zhang Zhung was the last and most important war of conquest launched by Songtsen Gampo.

In March of 646 AD, after Tang dynasty's Emperor - Tang Taizong led his army to victory in Liaodong, he returned to the capital (now Xi'an, Shaan'xi province). In July, Tibet sent a delegation led by Tubo's prime minister -- Lu Tongtsan to the Tang capital to congratulate Tang Taizong on his victory and referred Tubo Kingdom to Tang dynasty as "son-in-law".

In 648 AD, Wang Xuance, a Tang envoy, was sent to India. He arrived during a period of turmoil as the Eastern Indian king Aruna-Shrona and Siladitya were fighting for power. Wang Xuance and his delegation of 2000 people were robbed and murdered. Wang Xuance fled to Lhasa and asked for help. Since Tubo Dynasty and Tang Dynasty had just established friendly relations and Princess Wencheng was living in Lhasa, Songtsen Gampo immediately sent an expeditionary force consisting of 1200 Tibetan soldiers and 7000 soldiers from the vassal state of Nepal to quickly attack India. They quelled the turmoil in Eastern India, allowing the Tang envoy to return safely and bringing back prisoners to the capital of Tang Dynasty of Chang'an (Now, Xi'an Shaan'xi province). Although the Tibetan army occupied Central India at the time, they did not stay long. The Til Lake area in northern India was incorporated into the territory of the Tubo Dynasty

In the same year, Tang Dynasty joined forces with the Turks, Tibetans, and Tuyuhun to defeat Kucha, capture their king Baihelibu Shibai alive, and move the "Anxi Protectorate" to Kucha, governing Hotan, Shule, and Suyab. From then on, Kucha, Hotan, Shule, and Suyab were collectively known as the "Four Towns of Anxi" and became the main force in the struggle against Tubo Dynasty in the region.

Also in the same year, Songtsen Gampo sent Thonmi Sambhota, who later created Tibetan script,and others to study in India.

In 649 AD, Tang Dynasty's Emperior -- Tang Taizong passed away and was succeeded by Tang Gaozong who appointed Songtsen Gampo as the head of the imperial guard and granted him the title of Prince of the West Sea. Tubo Dynasty immediately expressed its loyalty by offering fifteen kinds of gold, silver, and jewelry, which were placed in front of Taizong's memorial tablet. Tang Gaozong praised him and promoted him to the rank of King.

Songtsen Gampo requested silk worms and craftsmen for making wine, paper, and ink from the Tang Dynasty

In 650 AD, Songtsen Gampo passed away and was succeeded by his grandson, Mang Song Mang Zan, who became the Tibetan king. In May of the same year, he sent an envoy to Tang Dynasty to report the death and explained that Songtsen Gampo's son had died early, so his grandson was enthroned as king while still young. The Tang Dynasty sent an envoy to Lhasa to offer condolences.

Lu Tongtsan became the regent and held the actual power of the Tibetan kingdom for over 50 years. He inherited Songtsen Gampo's political policies and gradually improved the laws, checked household registration, determined taxes, and stabilized Tibet internally.

Note: The birth and death dates of Songtsen Gampo remain uncertain and there are various opinions. Tibetan historical books generally believe that he lived to the age of 82, but there are different accounts regarding his specific birth and death years, some of which have obvious calculation errors. The contemporary academic community has debated this issue, with some advocating that Songtsen Gampo lived to be 34 years old. There are also scholars who believe that Songtsen Gampo lived to be 58 years old.

In 651 AD, Tubo Dynasty held a grand funeral for Songtsen Gampo and buried him in the royal tomb in Qonggyai County. His tomb is still preserved today, with a mound as high as a small hill and a temple dedicated to him and his wife.

Songtsen Gampo unified all the tribes in the Qinghai-Tibet Plateau under the Tibetan kingdom, which began to rise as a powerful Tibetan political regime. He opened up the previously isolated region politically, economically, and culturally, developing it into a prosperous area with extensive contacts with the outside world. His glorious achievements made him the most revered Tibetan monarch by future generations.

In the year 652 AD, the army of Tubo dynasty was led by Lu Tongtsan, and captured the two areas of "Lowo" and "Zanger Xia".

In 653 AD, Lu Tongtsan made every effort to reorganize taxation and formulated the "cow-leg tax". The implementation of livestock taxation enabled the Tubo Dynasty to tightly control livestock producers, collect taxes on time, and strengthen management of nomadic tribes without fixed residence. At the same time, it ensured government revenue and the tax system was more complete than before.

This year, "Khu mang po rje" was in charge of collecting agricultural taxes and appointed Finace officials of Zhang Zhung

In 654 AD, Lu Tongtsan held a meeting in Mongbusailazong to distinguish between "Gao" and "Yong". The former refers to the warrior class who joined the army, while the latter refers to people with low status engaged in production. Some directly translated "Yong" as slaves. Songtsen Gampo had also distinguished between "Gao" and "Yong".

In the same year, Lu Tongtsan conducted the earliest recorded census in Tubo and established a household registration system, which provided a reliable basis for conscripting laborers, recruiting soldiers and horses, and collecting food and grass, known as the "big material collection".

In 655 AD (five years after Songtsen Gampo's death), Lu Tongtsan formulated the first law in Tubo's history, the "Six Great Laws". This is the most clear chronological record of Tubo's written law promulgation.

In 656 AD, Lu Tongtsan activated the collection of "cow-leg-taxes" in "Maer" of "Zanmu area". Then he began to launch wars against the northwest and east regions of Tubo Kingdom separately.

Tubo army first attacked the important town of the Silk Road, Xiaobolu (now Gilgit, Pakistan). Then in the 12^th month of that year, he personally led an army of 120,000 to attack the remnants of Bailan which was with extremely close relations with Tuyuhun kingdom, and completely defeating the Bailan tribe, which lost its independence and became a subject of Tubo kingdom. In order to avoid pressure from the Tang Dynasty, Lu Tongtsan adopted an active and friendly strategy to Tang Dynasty

In 657 AD and 658 AD, Lu Tongtsan toured the "Ningzhong" area and sent envoys to offer tribute to Tang Dynasty and request marriage alliances.

In the year 659 AD, Lu Tongtsan launched a war against the Tuyuhun Kingdom and stayed there for 7 years until 666 AD.

In the same year, the Tubo general Dargya Mangpoje fought against the Tang general Su Dingfang at "Dongdai" (now, Wuhai, Qinghai province). Dargya Mangpoje died and his army of 80,000 was defeated by only 1,000 Tang soldiers.

Note: Some scholars speculate that this battle may be the same as the one mentioned in Volume 200 of the "Zizhi Tongjian", which describes the attack on Tuyuhun by the Tubo army led by Lun Trinring. However, the dates do not match.

Scholars have inserted this battle into the Tibetan History Draft, which only records the Tuyuhun attacked by Tubo army in 659-660 AD and makes no mention of a conflict with Tang Dynasty. Currently, there is no consensus among scholars regarding the interpretation of historical material related to this battle, such as location, outcome, and troop strength. For example, Wang Yao believes that the Tang army of one thousand defeated the Tibetan army of eighty thousand, while Gengdun Qunpei and Huang Zhengjian believe that the Tibetan army of one thousand defeated the Tang army of eighty thousand. Huang also argues that the "Tibetan Annals" do not record Tibetan defeats and that there is no record in Chinese literature of Su Dingfang's conflict with Tubo army at that time.

Therefore, it may have been a small battle in which the Tibetan army of eighty thousand defeated the Tang army of one thousand. As for the identity of Dargya Mangpoje, some scholars believe that he was the leader of Tuyuhun who was friendly to Tubo Dynasty in the vicinity of Lake Uhai, while schoolar Wang Zhong believes that he was Murong Zunwang stationed in Shanshan region.

In 660 AD, the Tibetan Empire's Prime Minister, Lu Tongtsan, sent his son Lu Trinring to lead an army to attack the Tuyuhun Kingdom. In the same year, the Tubo army seized and control the Wakhan Corridor.

In 662 AD, the Tubo army, for the first time, entered the Central Asian region through "Hu Mi". The Tibetans instigated pro-Tibetan forces in Shule(now, Kashgar in Xinjiang), Gongyu, and Kucha to revolt against the Tang Dynasty. This was coordinated with the Tibetan military actions in Qinghai, with the aim of dispersing the strength of the Tang Dynasty. The Tang Dynasty gradually lost control over the Anxi Protectorate's capital, "Kucha".

In the twelfth month of the lunar calendar, Tang General Su Haizheng led an army to suppress Kucha, and at the same time, he ordered the subordinate Tang prince, the Uighur Khagan Ashina Misheti, and the succeeding Khagan Ashina Buzhen to assist in the operation. Due to the enmity between Ashina Misheti and Ashina Buzhen, and Ashina Buzhen's false accusation against Ashina Misheti, Tang General Su Haizheng believed the false accusation and therefore planned to kill Ashina Misheti, annihilating the army of this tribal kingdom. When Su Haizheng's army reached the south of Shule (now, Kashgar in Xinjiang), the Western Turkic Gongyu Tribe (also known as Chuyue) led the Tibetan army to prepare to confront the Tang army. However, Su Haizheng used a very ancient method -- bribing the Tibetan army with military resources. The Tibetan army did not fight and instead profited, naturally agreeing to negotiate peace with Su Haizheng.

Note: Tibet's involvement indicates that the Tibetan Empire had some influence in the Western Regions at that time. Later, the remnants of Ashina Misheti's tribe regrouped and established themselves as the Left Wing Khaganate of the Western Turks, aligning themselves with Tibet and becoming a supporting force for Tibet's military campaigns in Central Asia.

In 663 AD, the Western Turkic tribes, including the Gongyu Tribe, defected to Tubo Dynasty, threatening the region of Khotan (in present-day southern Xinjiang). In the twelfth month of the lunar calendar, the Tang Dynasty appointed General Gao Xian as the overall commander to attack the Gongyu Tribe and rescue Khotan. However, the outcome of this campaign is not recorded in historical accounts.

In the same year, the minister of Tuyuhun Kingdom Su Hegui fled to Tibet, revealing all the truths of Tuyuhun's internal affairs to the Tubo Dynasty. Subsequently, Lu Tongtsan launched a final attack on Tuyuhun Kingdom. Tuyuhun sought aid from the Tang Dynasty, but the passive attitude of the Tang Dynasty led to continuous retreats by Tuyuhun in the face of the powerful Tibetan offensive. In the end, their king, Murong Nuohuopo, and Tang Dynasty Princess Honghua fled with only a few thousand people to the Tang Dynasty's Liangzhou(now, Wuwei city, Gansu province), seeking protection from the Tang Dynasty. With this, the Tuyuhun local regime was destroyed; the Tuyuhun had existed as an independent kingdom for 350 years until 663 AD, and their territory was completely incorporated into the Tibetan Empire's territory.

As a result, the majority of the Qinghai-Tibet Plateau came under the rule of the Tubo Kingdom, and there were no tribes or regimes that could contend with it. Lu Tongtsan brought an end to Songtsen Gampo's unification campaign. In the following years, Lu Tongtsan resided within the conquered territory of Tuyuhun, handling post-war affairs and establishing Tubo's governing system. According to later historical records, Tubo also implemented a system of thousand households in the Tuyuhun region, but retained the status of the royal family, and there were marital alliances between the Tubo royal family and the Tuyuhun royal family.

In 665 AD, the Shule and Gongyue tribes led the Tubo army to attack Khotan. The Tang Dynasty ordered the commander Cui Zhibian and others to lead troops to reinforce from the Western region (governed by Turpan in southeastern Xinjiang). According to a passage from the "Tong-Dian," it is known that Cui Zhibian used the tactic of besieging one to rescue another by launching a surprise attack on the rear of the Tubo army which caused great losses to the Tubo army, and they subsequently abandoned the siege of Khotan In the same year, Tubo dynasty sent envoys to the Tang Dynasty to seek restoration of the alliance with Tuyuhun tribe and requested grazing rights in Chishui to confuse the Tang Dynasty and achieve the goal of incorporating Tuyuhun tribe into their territory. However, the Tang Dynasty rejected this request.

In 666 AD, Lu Tongtsan fell ill on his way back from the Tuyuhun region and died the following year.

In 667 AD, in February, the twelve provinces of Shengqiang (also known as Zhuqiang of Jimi Prefecture) were conquered and annexed by Tubo Dynasty. In March, the Tang Dynasty abolished the administrative system of the twelve provinces in the Qiang region.

In the same year, the appointed leader of the Western Turkic Khaganate, Ashina Buzhen, died, and his general Li Zhepu declared independence and surrendered to Tubo Dynasty. From that time on, Tubo dynasty controled the entire Wakhan Corridor.

In the same year, the prime minister of Tubo dynasty Lu Tongtsan passed away due to illness, and was succeeded by his eldest son Gar Tsenye Dompu

In 668 AD, Mangsong Mangzan stationed at Lu Garden in Zhadi. Tubo built fortresses in Jima Guole (presumably in the eastern part of Tubo). That year, various tribes of the former Tuyuhun kingdom sent envoys to Tubo Dynasty, and Tubo began to collect taxes from the Tuyuhun, signifying the stabilization of Tubo's rule in the Tuyuhun area.

In 670 AD, in the fourth month of the lunar calendar, after several years of preparation, Tubo Dynasty launched a large-scale military campaign in the Western Regions. Tubo forces captured eighteen dependent Jimi states of the Tang Dynasty in the Western Regions, including Kucha Bahmicheng (now Aksu County in Xinjiang), Yanlei (Yanlei County in Xinjiang), Kucha (Kuche County in Xinjiang), Shule, Yutian （Khotan，Xinjiang), and other regions south of the Tianshan Mountains. Tubo Dynasty gained complete control over these territories, and the Tang Dynasty abolished the "Four Towns of Anxi". This marked Tubo's first major success in the Western Regions.

【Battle of Dafeichuan】

The Tubo Kingdom conquered the Tuyuhun kingdom in the east and occupied the "Four Towns of Anxi" in the west, posing a great threat to the stability of the western border of the Tang Dynasty. This forced the Tang Dynasty to seriously deal with Tubo's expansion. In the fourth month of the lunar calendar in 670 AD, Emperor Gaozong appointed General Xue Rengui as the commander-in-chief of the Lupo Dao expedition, with General Ashina Daozhen as the deputy and General Guo Daifeng as the vice-deputy. They led over 100,000 troops (actually 50,000) to attack Tubo.

From Xue Rengui's title as a renowned general, it can be seen that the goal of the Tang Dynasty's expedition was none other than the Tubo capital, Luozu (Lhasa), with the intention of completely destroying the Tubo power. The Tang army claimed to be "protecting the return of the Tuyuhun kingdom" and escorted the Tuyuhun king back to Qinghai. In August of the lunar calendar, Xue Rengui's troops entered Dafeichuan in Qinghai (southwest of Gonghe County in Qinghai), and he ordered Guo Daifeng to construct fortifications in Dafeichuan to store supplies. Xue Rengui himself led the elite troops to march towards Wuhai (southwest of Xinghai County in Qinghai).

At that time, Tubo dispatched the skilled commander Lu Trinring, the second son of Lu Tongtsan, leading over 200,000 Tubo troops to confront the Tang army. According to "Old Book of Tang - Biography of Xue Rengui," the Tubo army reached a maximum of 400,000 troops during this battle. Lu Tongtsan took advantage of his familiarity with the terrain and the advantage of Tubo troops being accustomed to fighting in high-altitude areas to lure the enemy deep into his defense. Xue Rengui led his troops rushing in and defeated a small group of Tubo forces at the mouth of a river. Meanwhile, Lu Trinring led his cavalry to attack the Tang army's supplies. At this time, General Guo Daifeng did not obey Xue Rengui's command and instead followed Xue Rengui's troops with the supplies, only to be besieged by Lu Trinring's army along the way. Guo Daifeng was defeated and the supplies fell into the hands of the Tubo army. Upon learning of Guo Daifeng's defeat, Xue Rengui dared not advance any further and had to retreat to Dafeichuan. Lu Trinring surrounded the heavily weakened Tang army from all sides, resulting in a major defeat for Xue Rengui's troops, with heavy casualties. Tubo achieved a comprehensive victory in the Battle of Dafeichuan.

Xue Rengui, Guo Daifeng, and Ashina Daozhen were the only ones who escaped with their lives and reached an agreement with Lu Trinring for their survival. It seemed that the three commanders were captured by Lu Trinring, otherwise the entire army would have been annihilated, and it was impossible to negotiate for their survival. Since the Battle of Dafeichuan, the Tuyuhun lost all hope of restoration, and the Tuyuhun king was placed in Lingzhou(now, Wuwei city of Gansu province). Lu Trinring's reputation spread far and wide from this point onwards. The victory in the Battle of Dafeichuan also consolidated Tubo's rule on the Qinghai-Tibet Plateau, firmly establishing control over the Qinghai Lake region. Furthermore, Tubo continued to vie with the Tang army for control over the Longyou Circuit, Hexi Circuit, and the four towns of Anxi, striving to gain control over the Silk Road and obtain greater economic benefits.

In the year 672 AD, the Tubo kingdom dispatched Minister Zhong Cong to visit the Tang Dynasty. Emperor Gaozong of Tang questioned Tubo's swallowing of the Tuyuhun tribe and the defeat of General Xue Rengui. However, Zhong Cong replied, "As a messenger, I have been tasked with making contributions. I am not aware of military matters." Tang Dynasty then sent Huang Rensu as an envoy to Tubo. Despite both sides sending envoys, no substantial progress was made in resolving border and other issues.

In 673 AD, Tubo Dynasty implemented a system of assembly meetings to decide major military and political affairs. This year, under the leadership of Gar Tsenye Dompu and Lu Trinring, they formulated major laws for governing pastoral areas. During winter, they held meetings at the "Dong" Tiger Garden to discuss matters, and conscripted young men to strengthen the army.

In the twelfth lunar month of this year, Tang Dynasty sent Xiao ciye to lead troops to suppress the rebellion of the Gongyue and other tribes who had betrayed Tang to Tubo. The Gongyue and Shule tribes feared the consequences and sent envoys to Tang Dynasty requesting surrender, which indicates that after Tubo captured the Anxi Four Towns in 670 AD, they failed to establish effective rule, and the various small states in the Southern route of the Western Regions returned to the Tang Dynasty's control. The Tang army also recaptured Kucha.

In the year 674 AD, the Tang army recaptured Yutian（now, Khotan, Xinjiang)

In 675 AD, the Tang Dynasty established the Pisha Dudufu in Yutian（now,Khotan, Xinjiang), with the Yutian King Yuchi Fuge Xiong as the commander, overseeing ten provinces. The King of Kucha, Baisuji, also offered tribute to the Tang Dynasty, and Tang established Dufu in Yanjing, Shule, and other places. By the year 676 AD, the Anxi Four Towns had returned to Tang Dynasty's control.

In the same year, Tubo Dynasty sent emissary Tu Hunmi to seek peace with Tang Dynasty and requested to restore friendly relations with Tuyuhun, but was rejected by the Tang Dynasty.

In the same year, the Grand Council under the leadership of Gar Tsenye Dompu formulated laws to govern the region of Zhang Zhung. News of internal turmoil in the Turkic territories also reached Tubo during this year.

In the year 676 AD, Tubo attacked and plundered several states including Shanzhou (now Ledu County, Qinghai), Kuozhou (now southwest of Hualong County, Qinghai), Hezhou (now Linxia City, Gansu), Jingzhou (now Jingchuan County, Gansu), Diezhou (now southeast of Diebu County, Gansu), and Fuzhou (now northeast of Jiuzhaigou County, Sichuan). They killed Tang Dynasty officials and seized tens of thousands of horses and cattle. The Tang Dynasty dispatched troops to suppress the Tubo army but was unsuccessful. Tubo army also attacked Diezhou (now Diebu County, Gansu) and captured the counties of Migong and Danling.

In the same year, according to the "Annals of Major Events", Ryeshin khubu lbu and Cogring Tsukor harbored different ambitions and launched a rebellion in Zhang Zhung. The rebellion was suppressed by the Tubo dynasty the following year.

In the same year, Tubo army launched attacks in the Western Region and recaptured Kucha.

In the same year, when winter arrived, the Tubo ruler, Mangsong Mangzan, passed away, and the Tubo army ceased military operations. Mangsong Mangzan ruled for twenty-seven years. His remains were temporarily placed in "Balanmu" in 677 and 678 AD and were finally buried in 679 AD.

In the same year, Mangsong Mangzan's posthumously born son, Dusong Mangpoje, was born seven days after his father's death. He was immediately proclaimed as the ruler and given the name Tridu Songtsen while Lu Trinring continued to handle governance. During this period, Tubo was at a disadvantage in the Western Region, so they turned to attacking the southwest and seized several important military locations of Tang Dynasty along the Min River.

Note: There is still debate among historians about the exact year of Mang Song Mangzan's death, whether it was in 676 or 677 AD.

Note: Tridu Songtsen（676-704) was also known as Dusong Mangpoje, and according to Tibetan tradition, he was the 35th ruler of the Tubo Dynasty, reigning from 676 to 704 AD. Due to the long-term monopolization of power by the Gar clan, conflicts arose with other nobles, posing a threat to the consolidation of the ruler's authority. When Tridu Songzan grew up, he attempted to eliminate the influence of the Gar clan.

In 677 AD, in the fifth month of the lunar calendar, the Tubo Empire launched a war against the Tang Dynasty on the eastern border, attacking the town of Linhe in Fuzhou (northeast of Jiuzhaigou County, Sichuan) and capturing the general Du Xiaosheng. Emperor Tang Gaozong of the Tang Dynasty issued a decree called "Seeking Brave Warriors," ordering a large army to retaliate against the Tubo army.

In the same year, the rebellion in the northwest region of Tubo, known as the "Zhang Zhung Rebellion", led by Ryeshin khubu lbu and Cogring Tsukor, was suppressed by Tubo army.

In the same year, the Tubo army launched attacks on the Tang army guarding the four towns of Anxi in the Western Regions.

In 678 AD, two traitors, "Rasang je Pungye yung" and "Kutri Nyadru Zung" were punished. Their identities were unknown, but the literal meaning of "Rasang je" can be understood as "the king of Rasang tribe (or region)."

While Tubo focused on resolving internal conflicts, the Tang Dynasty organized a military counterattack. Li Jingxuan, the Minister of the Imperial Secretariat, and Liu Shenli, the Minister of the Ministry of Works, led an army of 180,000 troops to march from Heyuan to Tubo. The Tubo general, Lu Trinring, led the Tubo army to confront them near Qinghai Lake. Liu Shenli's vanguard troops were attacked by the Tubo army, resulting in their defeat and Liu Shenli being captured. The Tang army commander, Li Jingxuan, became fearful and retreated upon hearing of the vanguard's defeat. The expedition of the 180,000-strong Tang army came to an end, and Liu Shenli ultimately died in Tubo Dynasty.

In the same year, Tubo captured the four towns of Anxi for the second time on the western front, while also capturing the city of Anrong (now Mao County) on the eastern front.

In 679 AD, as internal and external troubles were temporarily eliminated, Tubo openly held a funeral and buried the deceased King Mangsong Mangzan. In October of the same year, Tubo sent an envoy to the Tang Dynasty in the name of Princess Wencheng to express condolences and request a marriage alliance. They specifically requested to marry the Tang Dynasty's Princess Taiping. Emperor Tang Gaozong of the Tang Dynasty dispatched General Lang Songling to attend the funeral of King Mangsong Mangzan, but politely declined the marriage alliance. By this time, Tubo had become a formidable enemy of the Tang Dynasty.

In the same year, the Western Turkic Khanate, which was allied with Tubo Dynasty, and another leader of the Western Turkic, Li Zhefu, joined forces with the Tubo army stationed in the Western Regions to attack the capital of Anxi Protectorate (the "Suiye Town," now, Tokmak). They were defeated by the army led by Pei Xingjian, the Minister of the Ministry of Personnel of the Tang Dynasty. At this time, Tubo dynasty was busy with the funeral of King Mangsong Mangzan and had no time to send reinforcements to the Western Turkic tribes. The Western Turkic tribes returned to the rule of the Tang Dynasty, and the Tang Dynasty reestablished the four towns of Anxi, replacing "Suiye" with "Yanqi" as the new seat of the Anxi Protectorate.

Note: The Western Turkic Khanate was originally a Khanate located to the west of the Turkic Khaganate. After the Turkic Khaganate's defeat in wars against the Tang Dynasty, it split into eastern and western factions. Shitidianmi, located in the western part of the Khanate, gathered various scattered 10 tribes and granted one arrow for each of the ten tribal leaders. Therefore, these ten tribes are also known as the "Ten Arrows tribe" which retained considerable strength and were able to dominate the Western Regions and control the Silk Road.

In the year 680 AD, in the 7th month of the lunar calendar, the Tubo army attacked Heyuan（now, Xining City, Qinghai province）, but was repelled by General Heichi Changzhi of the Tang Dynasty.

Heichi Changzhi was appointed as the Chief and Strategist of Heyuan Army. He established more than seventy beacon towers and cultivated over five thousand hectares of farmland, effectively blocking the eastward expansion of Tubo Dynasty.

Then, Tubo army turned their attention to present-day Sichuan and Yunnan. In earlier years, the Tang Dynasty had built the Anrong City to cut off Tubo's access to various Minority tribes. In this year, with the assistance of Qiang people in its southwest, the Tubo army captured the important pass leading to Nanzhao, the Anrong City (now Xuecheng Town in Sichuan and parts of Mao County), and stationed troops there. Subsequently, Tubo's influence reached Yunnan, and various tribes in Xi'er (now the Erhai Lake area) surrendered to Tubo force. This was Tubo's first breakthrough in Yunnan.

With Lu Trinring brothers launching attacks from all sides, Tubo's territory continued to expand. Historical records state that Tubo controlled the eastern regions of Liang zhou, Song zhou, Mao zhou, and Ju zhou, bordered the kingdom of Tianzhu(Now, India) to the south, occupied the four towns of Kucha, Shule, and others to the west, and reached as far as the Turkic Empire to the north. Its territory spanned over ten thousand miles from east to west, and its power and influence among all tribes were unrivaled.

In the same year, Princess Wencheng, who had lived in Tubo for nearly 40 years, passed away, and Emperor Tang Gaozong sent envoys to Lhasa to hold a memorial ceremony.

Note: Regarding the time Princess Wencheng lived in Tubo, according to the Tibetan "Han-Tibetan Historical Collection," Princess Wencheng arrived from the Central Plains in the 641 AD and lived in Tubo for 58 years (page 121 of the book). If we calculate based on this information, it should be around 698-699 AD.

In 681 AD, in the 5th month of the lunar calendar, Tubo general Lu Tsanba led troops to invade Qinghai but was defeated by the Tang Dynasty general Heichi Changzhi at the Liangfei Plain.

In the same year, Tubo sent envoys to the Tang Dynasty again to propose a marriage alliance and request Princess Taiping's hand in marriage again, but it was again rejected by the Tang Dynasty.

Starting from this year, another member of the "Gar" family, Gar·Mangnyen Tagtsab, became active in the political arena of Tubo Dynasty.

In this year, Prime minister Tsan Nya held a meeting in the Silide River Valley, while Gar·Mangnyen Tagtsab and Nubu Mangnye Shitsan held a meeting in the "Jia Valley".

In 682 AD, Tubo general Lu Trinring led his troops to attack Zhezhou (in the border area of Heishui County and Li County, Sichuan) and Yizhou (north of Maowen County, Sichuan). They also attacked Heyuan (Xining City, Qinghai) and were defeated by Tang general Lou Shide at the Baishui Gorge. Lou Shide had a record of "eight battles, eight victories".

In the year 683 AD, Tubo Dynasty held a grand ceremony to worship Princess Wencheng.

In 684 AD, Tubo held a meeting in the central area "Ru" of Tubo dynasty to resolve disputes in Tubo's territories, including Tuyuhun.

At the same time, there was an outbreak of cattle plague in Tubo. In order to reduce the spread, the infected cattle were buried in a centralized manner. Natural disasters and other factors temporarily halted Tubo's military activities.

In 685 AD, the conflict between Prime Minister Gar Tsenye Dompu and Gar Mang Nyen Tagtsab became public, resorting to violence. The internal turmoil of Tubo Dynasty was quickly quelled by Lu Trinring, but "Gar Mang Nyen Tagtsab" disappeared from historical records thereafter.

In the same year, Prime Ministers Gar Tsenye Dompu passed away, and his brother Lu Trinring succeeded him as the Prime Minister of Tubo Dynasty. The internal strife of the Gar clan did not affect their position, and the Gar clan still held power over Tubo Dynasty. The situation quickly returned to peace and stability.

In the same year, the ministers of Tubo bestowed the honorary title of "Tridu Songtsen" to the young Tubo Emperor "Dusong Mangpo je".

In the same year, Tubo Dynasty sent a golden ball to the Tang Dynasty, recorded as "Golden Bolo" in the "New Book of Tang". The term "Bolo" is equivalent to "polo" in English, referring to the sport of polo. American scholar Berthold Laufer(1874—1934 believed that the English word "polo" originated from the Tibetan language in his book "Loanwords in Tibetan". The "Old Book of Tang" records: "In the eleventh month of the third year of Jinglong (709 AD), the minister Zhang Tsanto and others were sent to escort the princess. Emperor Tang Zhongzong hosted a banquet at the palace's polo field, and ordered the Imperial Guard Yang Shenjiao and the Tubo envoy to play polo. Emperor Tang Zhongzong and his attendants watched the game." The "Fengshi Wenjianji" provides a detailed description of the polo match between the Tang and Tubo, stating that Tubo initially won several rounds, but it was only when the Xuanzong, who was then the Prince of Linzi, personally joined the game that the Tang Dynasty won. At that time, there were ten players from Tubo, and the fact that there were so many skilled polo players in one envoy reflects the Tubo people's love for this sport.

In 686 AD, in the 9th month of the lunar calendar, the Tang Dynasty appointed General Ashina Husele to inherit his father's title and assume the position of Jueke Khan, concurrently serving as the commander of Mochi, leading the tribes of the Western Turkic Khaganate. The Tang Dynasty began to take a series of measures to counter Tubo's infiltration in the Western Regions.

In the year 687 AD, Tubo's prime minister Lu Trinring led the Tubo army to invade the Western Regions and attacked Kucha. The Tubo army captured the city of present-day Kashgar and gained control over the Western Regions.

In 688 AD, Empress Wu Zetian of the Tang Dynasty planned to launch an attack on Tubo from Yazhou (located in the west of Yaan County, Sichuan Province), attacking Tubo from the southwest. Tubo's Prime Minister Lu Trinring still commanded troops stationed in the Western Regions that year.

In the year 689 AD, in the 5^th month of the lunar calendar, the Tang Dynasty dispatched General Wei Daijia as the commander to attack Tubo army in the west region. However, in the 7^th month of the lunar calendar, the Tang army was defeated by Tubo army at Yinshijia River, southwest of Gongyue (north of Talerqi City in Huocheng County, Yili Prefecture). The Tang army suffered heavy losses. Due to his victory, Lu Trinring returned to Lhasa from the Western Regions.

In the same year, a princess of Tubo married the king of Tuyuhun. Although Tuyuhun was under the rule of Tubo, Tubo still retained its royal lineage.

In the same year, "Bangshiku" (the leader of Langqiongzhao, one of the Six Zhaos of Yunnan Minority) led twenty-five surrounding tribes to switch allegiance from Tubo to the Tang Dynasty.

In 690 AD, Lu Trinring personally presided over two meetings to reform internal affairs in Tubo Dynasty. He established the Red-book system and formulated regulations on agricultural land taxes in "Yue Ru"

In 691 AD, Tubo Dynasty cleared land taxes throughout the territory and conducted a census of the population, as well as conscripting soldiers. The council originally scheduled to be held in Sewu was relocated to Chana and personally presided over by the Tsanpu (Tubo's ruler) Tridu Songtsen, who was only 16 years old at the time. This should mark the beginning of the young Zanpu's attempt to regain power from the prime ministers

In the same year, Empress Wu Zetian of the Tang Dynasty ordered her ministers to attack Tubo, but they later withdrew.

Note: The Gar clan had posed a great threat to Tubo's royal authority. At this time, Tubo's retreat from the Western Regions and Lu Trinring's expansion were thwarted, providing an opportunity for the ambitious young Tsanpu(Tubo's ruler). The conflict between the royal family and the Gar clan deepened, and the determined Tsanpu quietly began his campaign to regain power.

In 692 AD, more than 10,000 members of the Minya tribe surrendered to the Tang Dynasty, and the Tang Dynasty established ten prefectures for them.

In the 5^th month of the lunar calendar, Tubo chieftain He Su also requested to surrender to the Tang Dynasty. Tang sent General Zhang Xuanyu to lead 20,000 elite soldiers to welcome him. However, when they reached the Dadu River, their plan was exposed, and Tubo Dynasty arrested He Su.

In the same year, Jiu Chui led more than 8,000 Qiang troops to surrender to the Tang Dynasty.

In this situation, although Tubo Dynasty gained power in the Western Regions, however, they were unable to further expand.

In the 10^th month of the lunar calendar, Tang generals Wang Xiaojie, Tang Xiujing, and Ashina Zhongjie launched a western campaign against Tubo, defeated the Tubo army, recaptured the four towns of Anxi (Kucha, Kotan, Shule, and Suiye), and established the Anxi Protectorate in Kucha, stationing troops there. Tubo Dynasty's development in the Western Regions was dealt a setback.

In 693 AD, Lu Trinring went to the Tubo area of Tuyuhun, where the Gar clan had considerable influence. Lu Trinring remained stationed in the east border of Tubo dynasty.

In the same year, Tubo army launched an offensive in the western front, sending a large army to besiege Shazhou (now Dunhuang, Gansu Province). Tang dynasty's general Li Wukui led his troops to engage in battle but was seriously wounded and died.

In 694 AD, in the 2^nd month of the lunar calendar, Tubo general and Gar clan member Gar Tsanyen Gungton and Western Turkic Khan Ashina Tugushi led their army southward and were once again defeated by Tang general Wang Xiaojie in places like Lengquan (near Qinghai Lake) and Dalin (on the Qinghai border). Gar clan member Gar Tagu was also captured by the Sogdians. The defeated Turkic Khan Ashina Tugushi fled to Tubo.

In the same year, Han Sizhong, the garrison commander of Suiye, one of the four towns of Anxi, defeated the Tuyuhun leader Nishushijing and the Turkic Khan Shizhihan, capturing the Tubo city of Nishushimesi.

In 695 AD, under the pretense of defeat in the Western Regions, Tsanpu Tridu Songtsen executed Lu Trinring's younger brother Gar Tsanyen Gungton

In 696 AD, due to the Tang Dynasty's military victories in the Western Regions, Empress Wu Zetian of Tang dynasty wanted to launch an attack on Tubo army from the Qinghai. Wang Xiaojie was appointed as the Grand Commander of the Su-Bian Military Expedition, and Lou Shide was appointed as the Deputy Commander to attack Tubo army.

In the 3^rd month of that year, they fought against Lu Trinring and Tsan ba at Tao zhou (Lin Tan County, Gansu Province), on the Sulohan Mountain, also known as the Battle of Tiger Mountain according to the "Annals of Major Events". The Tang army was defeated, and many soldiers were killed. Tubo emerged victorious, and the battlefield on Sulohan Mountain (now Lihongdong in Gansu) was named "stag larya dur" meaning - "The Tang Burial Mound on Tiger Mountain" by Tubo.

Lu Trinring sent envoys to Tang dynasty requesting negotiations. Empress Wu Zetian of Tang dynasty sent Guo Yuanzhen, the former military officer of Zizhou Tongquan County, to meet with Lu Trinring in the Yehu River in Qinghai. The "Comprehensive Collection of Chronicles" provides a detailed account of their dialogue. During the meeting, Lu Trinring requested that the Tang Dynasty withdraw its troops from the four towns of Anxi and divide the territories of the ten tribes of the Turks, allowing each tribe to govern itself, not being under the rule of the Tang Dynasty or Tubo Dynasty. Guo Yuanzhen believed that the ten tribes had long been included in the Tang Dynasty's population register and proposed that Tubo return the territory of the Kingdom of Tuyuhun. Both sides presented compelling arguments but failed to convince each other.

Meanwhile, as Lu Trinring achieved greater military success, his reputation grew, and Tsanpu of Tubo dynasty, Tridu Songtsen, became more suspicious of the Gar clan.

In the same year, Tubo army launched an attack on Liangzhou (now Wuwei City, Gansu), capturing and killing the Governor of Liangzhou, Xu Qinming.

Note: During the reign of Empress Wu Zetian, the Tang Dynasty launched counterattacks against Tubo. Although the outcomes varied, the active decision-making of the Tang Dynasty (under Empress Wu Zetian) curbed Tubo's aggressive expansion, forcing Lu Trinring to refrain from sitting comfortably in Lhasa and had to personally oversee the front lines with the Tang and Tubo dynasties. According to the "Dunhuang Ancient Tibetan Manuscripts" (1.0.750), "The Chronicles of Major Events of Tubo," Lu Trinring stayed in the Kingdom of Tuyuhun from 693 AD until 698 AD.

In 698 AD, Lu Trinring led troops to Dazongka and Xiaozongka (in the vicinity of Huangzhong County, Qinghai Province), capturing the Vice Governor of Tang Dynasty which was unrecorded in Tang history

In the same year, Tupo Tsanpu Tridu Songtsen gradually diminished the power of the Gar clan and, under the pretext of hunting, gathered his troops to execute over two thousand followers of Lu Trinring. He then sent troops to suppress Lu Trinring, who did not follow his orders. Lu Trinring's army, loyal to Tupo Tsanpu Tridu Songtsen, disintegrated without fighting, and Lu Trinring committed suicide. After the downfall of the Gr clan, Tubo Dynasty lacked capable generals and often found themselves at a disadvantage in their conflicts with the Tang Dynasty. From 691 AD to 698 AD, Tridu Songtsen spent eight years reclaiming his political power and resumed his rule.

In 699 AD, after the death of Lu Trinring, his younger brother Tsan ba and Lu Trinring's son Gar Mangpoje led their respective forces of over a thousand people to surrender to the Tang Dynasty. They were settled in the Hongyuan Valley in Liangzhou (now Gulang County in the southeastern of Wuwei County, Gansu Province) as a defense against Tubo army. The Tuyuhun forces led by Gar Mangpoje also surrendered to the Tang Dynasty.

In the seventh month of the lunar calendar, another 1,400 tents of the Tubo tribe surrendered to the Tang Dynasty. This was a great loss for Tubo. Empress Wu Zetian of the Tang Dynasty welcomed the arrival of Tsan ba and Gar Mangpoje.

And a Tang envoy named "Zhou Shangsho" was sent to the Tubo dynasty (unrecorded in Tang history).

In the same year, the Western Turkic Khanate's leader Yehu Khan (Tonyabgokhagan) went to pay homage to the Tubo dynasty.

In 700 AD, Yehu Khan returned to the Western Turkic Khanate from Tubo Dynasty.

In this year, Tridu Songtsen dispatched the Tubo general Ku Mangpo Je to lead army attacking Liangzhou (now Wuwei City, Gansu Province), besieging Changsong County (now southeastern Gulang County, Gansu Province), where Tsan ba was stationed. This military campaign also aimed to punish Tsan ba of the Gar clan. However, the Tubo general Ku Mangpo Je, who was not skilled in military affairs, was defeated by the Tang generals in the Hongyuan Valley (now Gulang County in the southeastern of Wuwei County, Gansu Province).

In autumn, Tubo Tsanpu Tridu Songtsen sent troops to attack Hezhou (now Linxia City, Gansu Province), but the campaign was unsuccessful.

In winter, a Tang envoy named "Ma Dashi" was sent to Tubo dynasty which was unrecorded in Tang history

In 701 AD, the Tibetan Empire formed an alliance with the Turks, and together they attacked Liangzhou (now Wuwei City, Gansu Province), Songzhou (now Songpan County, Sichuan Province) and Taozhou (now Lintan County, Gansu Province).

In 702 AD, Tubo's King Tridu Songtsen personally led more than 10,000 people to attack Xizhou (southeastern Heishui County, Sichuan Province), but they were repelled by the defending troops of Tang dynasty. Tridu Songtsen then turned to peaceful diplomacy.

In the 9^th month of Lunar calendar, a Tubo envoy was went to the Tang Dynasty to seek peace.

In the 10^th month of Lunar calendar, Tubo attacked Maozhou (now Mao County, Sichuan Province), and the Tang Dynasty defenders fought against them, successfully repelling the Tubo army.

In 703 AD, in the 4th month of Lunar calendar, Tubo sent envoys to the Tang Dynasty with a tribute of 1,000 horses and 2,000 taels of gold to propose marriage to a Tang princess.

In summer, a Tang envoy named Gan Jing (Kam Keng) went to Tubo.

In winter of the same year, Tridu Songtsen personally led an expedition and invaded Nanzhao kingdom (present-day Yunnan), subjugating it.

In 704 AD, in spring, Tride Zuktsen was born.

The king of Nanzhao in Tubo kingdom's southwest paid tribute, and the Black Miao tribe became a vassal. During the time when Tridu Songtsen went to Nanzhao, there was a rebellion in Nanzhao. Tsanpu Tridu Songtsen personally led the army to suppress the rebellion, but unfortunately died in the army at the age of 29. His son, Labapo, who was born shortly and was less than one year old, succeeded to the position of Tubo Tsanpu. His grandmother, Bo Tri Malo, the wife of Mangsong Mangzan, acted as regent and supported her grandson.

In the same year, Tubo army launched an attack on Taimermez on its western front.

In this year, Tubo dynasty also forced the king of Nanzhao, located in their southwest, to pay tribute, and the Black Miao tribe submitted.

Note: Tridu Songtsen was not buried until the year 706 AD. The body was preserved for a period of three to four years. This was possibly due to waiting for the completion of the tomb construction and also in accordance with the Tubo tradition of holding long mourning rituals and performing certain treatments on the body.

Note: Labapo was a member of the royal family of the Tubo Empire. He may have briefly ruled Tubo between 704 and 705. His name is not mentioned in later Tibetan Buddhist history books, but it is recorded in the Dunhuang Tibetan manuscript "Chronicle of Events" and is referred to as Qilibabu in Chinese historical texts like the "Tongdian."

Note: Taimermez, also known as Termiz, is the capital of Surxondaryo Viloyati in Uzbekistan. It is located on the northern bank of the Amu Darya River, at the Uzbekistan-Afghanistan border, serving as a transportation hub between the two countries. Taimermez is known for its fertile land and developed agriculture.

In the year 705 AD, Degren Pa-non-nang-drag and Kegad Donang launched a rebellion. Bo Tri Malo took decisive action and sent troops to kill the rebels on the top of Nara Mountain. However, as one wave subsided, another wave rose. Similar unrest occurred within the territory of the vassal state of Nipolo (now, Nepal), and a member of the Tubo royal family who served as the king of Nipolo (referred to as "Tsanpo cen" in the "Chronicle of Events") was forced to retire. Bo Tri Malo appointed Ku Mangpo Je as the prime minister, but he was soon dismissed for his crimes and Da krigzig Zhangnyen was appointed as the prime minister.

However, another rebellion occurred within the territory of the vassal state "Xili". Regarding Xili, the "Cefu Yuangui" (Volume 960, Outer Ministers, Local Customs 6) states: "Xili is located in the southwest of Tubo kingdom, with a population of 50,000 households and an army of 50,000 soldiers. There are cities, towns, and villages in the area. They are subject to Tubo and have never been in contact with China."

With the Empress Dowager in power and the young Tsanpo, coupled with the extermination of the Gar clan, Tubo dynasty suffered a great loss of vitality, lacked military and political talents, and the regime was unstable, making rebellions within the vassal states inevitable.

In the same year, Bo Tri Malo deposed Labapo and enthroned Tride Zuktsen (originally named "Gya Tsuru"), the 2-year-old son of Tridu Songtsen.

In the 7^th month of the lunar calendar, Tubo dynasty sent envoys to the Tang Dynasty to announce the death of Tridu Songtsen.

In 706 AD, Minister Lo Dusu was punished, and power struggles within the Tubo dynasty became intense. While Bo Tri Malo consolidated power internally, they also sent envoys to the Tang Dynasty to propose marriage, continuing the marriage alliance policy of the Tridu Songtsen.

In the same year, the Tang Dynasty and Tubo Dynasty held the first border demarcation meeting, known as the "Shenlong Alliance," and defined the boundaries in the Qinghai region.

In 707 AD, the Tang Dynasty sent Tang Jiuhui to lead an army to attack the Xizai tribe, according to the "New Book of Tang - Tubo Biography." Tang Jiuhui led his army destroying the Yuanyi City built by Tubo army. The competition and wars between the Tang Dynasty and Tubo Dynasty in various tribes regions also provoked the Erhai tribes, leading to internal divisions among the Tribes in present-Yunnan and gradually moving towards unity.

In the same year, the Tubo envoy brought tribute to the Tang Dynasty and proposed a marriage alliance for Tride Zuktsen, the grandson of Bo Tri Malo. Tang Zhongzong responded to Tubo's friendly gesture and accepted the proposal, agreeing to marry his adopted daughter, Princess Jincheng, who was only 14 years old, to Tubo Tsanpo Tride Zuktsen.

Since 708 AD, the Tang Dynasty and Tubo Dynasty referred to each other as "nephew -- Tubo Dynasty" and "uncle -- Tang dynasty," which began in 708 AD. However, both sides had huge different interpretations of the "uncle-nephew relationship".

In 709 AD, Tubo suppressed the rebellion of Xili and captured the king of Xili. As the political situation in Tubo Kingdom was relatively stable, in the same year, Tubo Kingdom sent a large entourage, including the maternal uncle of the emperor, Zhangtsanto Relayin, and the minister Zhang gintzang, to the Tang Dynasty to welcome and marry Princess Jincheng.

In 710 AD, the Tang Dynasty dispatched General Yang Ju, the Left Guard General, to escort Princess Jincheng to Lhasa, the capital of Tubo dynasty. Emperor Tang Zhongzong of Tang dynasty and his officials personally accompanied them to Shiping County (Xingping County, Shaanxi), where they held a grand farewell banquet. Tubo envoys bribed General Yang Ju, who was escorting Princess Jincheng, to obtain the Hexi Nine Curves area (southeast of Qinghai Lake, the area on the west bank of the Yellow River) in the name of Princess Jincheng. Yang Ju then reported to the Tang Dynasty, and they agreed to cede the Nine Curves area to Tubo Dynasty. The Nine Curves area had abundant water, grass, and was an excellent natural pasture, so Tubo army established fortifications such as Hongji (west of Guide County, Qinghai) and Damomen (southeast of Gonghe County, Qinghai) there. This area became Tubo army's base for eastward expansion.

In the same year, Princess Jincheng arrived in Lhasa.

In the same year, Tubo's army conquered Baltistan in its western front, but they were attacked by Tang Dynasty's Anxi Governor Zhang Xuanbiao and General Li Zhigu in the northeast direction. In the southwest front of Tubo, Tang Dynasty's Imperial Inspector Li Zhigu captured the Yaozhou tribe who were originally allied with Tubo.

Note: According to the "Chronicle of Major Events," at this time, Tubo's Tsanpo Tride Zuktsen was only 7 years old, but Tubo, in a grand ceremony, married him to a princess of the Tang Dynasty, revealing the political significance of the marriage alliance. However, it seems that the Tang Dynasty was not aware of the true situation in Tubo. The "Old Book of Tang, Tubo Biography" records that Tride Zuktsen ascended the throne at the age of 7 and was already fourteen at this time, so it is likely that the Tubo people deliberately concealed the age of the Tsanpo from the Tang Dynasty. The Tubo dynasty were eager to obtain a princess from the Tang Dynasty to improve their reputation through this marriage alliance and ease the tense domestic situation, diverting people's attention. The Tang Dynasty married off a woman to achieve border security and peace, as stated in the poem of the marriage alliance, "Many ministers and strategists planned."

In 711 AD, the Tang Dynasty sent an envoy to Lhasa to inform Princess Jincheng that Emperor Tang Ruizong officially decided to adopt her as his daughter.

In 712 AD, Tubo's Empress Bo Tri Malo passed away. She had quelled a series of disturbances in Tubo Dynasty, maintained friendly relations with the Tang Dynasty, and brought stability to Tubo Dynasty. Bo Tri Malo was a highly accomplished woman in Tubo's history. In this year, Tubo's officials conferred the title of "Tride Zuktsen" on Tsanpo Gya Tsuru.

As Tride Zuktsen was young, regents such as Krizig Zhangnyen handled the affairs of the state.

In the year 713 AD, Tubo Dynasty began to designate summer pastures and winter pastures throughout its territory. This was conducive to the development of animal husbandry and improved the ability of livestock to safely survive the winter.

In the same year, during the summer, Tang envoy Yang Jing was appointed by the Tang Dynasty to visit Tubo.

In the year 714 AD, the Tubo court banished Zhongbadao Pengong.

In the fourth month of the lunar calendar, the Tubo Kingdom sent envoys to seek peace with the Tang Dynasty

In the sixth month of the lunar calendar, Tubo sent the envoy Zhang tintsang to Tang Dynasty, carrying the alliance documents for a meeting. Tubo and the Tang Dynasty held peace negotiations and signed a treaty, which stipulated that the border would be based on the Heyuan region (Now,Including Xinghai County, Gonghe County, Tongde County and Maqin County in present-day Qinghai Province). However, the agreement reached at the meeting soon became void

In the eighth month of the lunar calendar, the war broke out again. Tubo's senior minister Krizig Zhangnyen and General Bod dagyal led a 100,000 troops to attack Lin Tao (Min County, Gansu province), Lanzhou (Lanzhou City, Gansu province), and Weizhou (present-day Dingxi City, Gansu), plundering the Tang Dynasty's royal army and horses. Tubo army launched attacks on the Tang Dynasty from the Nine Curves area, instigating conflicts. Yang Ju, the Tang general who took bribes from Tibetan army fearing the situation, committed suicide.

In the tenth month of the lunar calendar, Tubo army attacked Wei Yuan (northeast of Weiyuan County, Gansu province). Emperor Xuanzong of Tang Dynasty issued a decree to personally lead the expedition, but the Tang generals Xue Ne and Wang Jun led a large army to severely defeat and repel Tubo army. The Tang Dynasty forces destroyed the castles and bridges that Tubo army had built in the Nine Curves area along the Yellow River. Afterward, the Nine Curves area continued to be engulfed in warfare. The "Tong Jian" states: "(Tubo army) continuously trespassed the border." In order todefend against Tubo's military attacks in the Hehuang region, the Tang Dynasty established the Longyou Jiedushi (governor) who governed over twelve states including Shanzhou, Qinzhou, Hezhou, Weizhou, Lanzhou, Linzhou, Wuzhou, Taozhou, Minzhou, Kuozhou, Diezhou, and Dangzhou.

After the Tibetan Empire requested to make peace, their request was rejected. After that, the relationship between the Tibetan Empire and the Tang Dynasty was sometimes tense and sometimes friendly.

Tubo dynasty later requested peace but was refused by Tang Dynasty. After that, the relationship between the Tubo dynasty and the Tang Dynasty fluctuated between tension and reconciliation

In 715 AD, Tubo and the Abbasid Caliphate jointly proclaimed A Leida as the king of Fergana. They sent troops to attack the Bahanna tribe (ancient Wusun tribe, now known as Fergana), but the king of Bahanna (formerly the king of Fergana) couldn't resist and sought help from the Anxi Governor of Tang Dynasty. The Tang Dynasty's army marched several thousand miles westward to Kucha and defeated A Leida, who fled into the mountains.

Because of this defeat, Tubo's forces retreated to the southern part of the Congling Mountains (Pamirs). This event marked the reemergence of Tubo dynasty on the Central Asian stage after years of silence and hinted at some level of understanding between Tubo and the Abbasid Caliphate.

Meanwhile, there were conflicts between Tubo and Tang's Beiting Duhu(Garrison). "In the second month of this year, Guo Qiancui was the commander of the Beiting Duhu and repeatedly defeated the army of Tubo and the Turkic Munuan. The spoils were countless, and their captives were presented."

Muden was the Khan of the Later Turkic Khaganate, also known as the Apakan Khan. This account indicates frequent interactions between Tubo and the Later Turkic Khaganate. Tubo dynasty was willing to establish relationships with many Western Regions tribes as long as it was beneficial to their own power.

In the early 8^th century, the Tujue tribe, originally belonging to the Western Turkic Khaganate, gradually grew stronger. They established Da Ye and minor Little Ye in the Shuiye chuan (Chu River Basin) and Yili shui (Ili River Basin). Tubo had close contacts with the Tujue tribe as well.

In 716 AD, in the 2^nd month of the lunar calendar, Tubo army launched an attack on Songzhou (present-day Songpan County, Sichuan), but was repelled by Sun Renxian, the commander of Songzhou.

In the 8^th month of the lunar calendar, Tubo dynasty sought peace through Princess Jincheng. Emperor Xuanzong of Tang Dynasty accepted the peace offering, and the Tang Dynasty sent envoys to present silk and other gifts to the Tubo Tsanpo, officials, and Princess Jincheng. The Tang Dynasty and Tubo Dynasty initiated peace talks.

In 717 AD, Tubo exiled the commander of the cavalry, Zhang Trinye Nyenlo. This was what The Tubo regime dealt harshly with disloyal officials, which might have been part of power struggles or factional disputes among the aristocracy.

That year, Tubo dynasty also conducted a census of the population registered in the nobles' manors.

In the same year, in the 3^rd month of the lunar calendar, the Tubo, Tujue, and Abbasid Caliphate united to seek control over the Anxi Four Towns. They launched an attack on the cities of Bohuan (present-day Aksu, Xinjiang) and Dashi (present-day Wushi County, Xinjiang) in the northwest of the Tarim Basin, but they were unsuccessful and were repelled by the troops led by Anxi garrison commander.

In the 7^th month of the lunar calendar, Guo Zhiyun, the military governor of Longyou, launched an attack on Tubo in the Nine Curves area and emerged victorious. He then presented the captured Tubo prisoners in Chang'an -- the capital of Tang dynasty. These captured Tubo soldiers were later distributed among the subordinate states of the Tang Dynasty and became registered households.

In that year, the Tubo army's attacks on the Tang Dynasty were completely repelled on both the eastern and western fronts. Tubo then sent envoys to request peace with the Tang Dynasty, and Princess Jincheng also sent letters to Tang dynasty to appeal for peace with the Tang Dynasty.

In 718 AD, the "Red Register" (a military household register) was established within the territory of Tubo to strengthen the collection of taxes and the conscription of labor and soldiers, as well as to enhance control over the local areas.

In the early period of Tubo, due to a lack of paper, important documents such as household registers, military rosters, tax records, and accounts were all recorded on wooden slips, serving as the basis for conscription and tax collection. Even in the late period of Tubo, wooden slips were widely used as well.

In the same year, General Guo Zhiyun of the Tang Dynasty led his troops to launch a surprise attack on the Nine Curves area, obtaining a large number of Tubo's elite armor, fine horses, and yaks. Emperor Tang Xuanzong of Tang Dynasty issued an edict to distribute the spoils to civil and military officials. The beneficiaries of the Tang-Tubo war were often the ruling class.

In the 11^th month of the lunar calendar, Tubo dynasty sent envoys to request a renewed alliance and proposed a sworn document with the titles of "uncle" and "nephew," with the names of prime ministers listed on it. Howeve, there was a significant difference in the understanding of the "uncle-nephew relationship" between the Tang dynasty and Tubo dynasty

In 719 AD, Tubo dynasty sent envoys to request the emperor's personal endorsement of the alliance document. Emperor Tang Xuanzong refused on the grounds of past treaties, but he and the empress sent generous gifts to the Tubo ruler and officials. In the following years, there was no military activity in the Hehuang region, and a period of peace was maintained.

Note: "Hehuang area" is also known as "Hehuang River Basin" and "Hehuang Valley"; It is a fertile triangular region located in the eastern agricultural area of Qinghai Province, consisting of the drainage basins of the Yellow River and the Huangshui River. From east to west, it includes Minhe County, Ledu County, Ping'an County, Huzhu County, Xining City, Datong County, Huangyuan County, Huangzhong District, Hainan County, Xunhua County, Hualong County, and Jinta County. This area features diverse landscapes and is one of the earliest inhabited regions in the Yellow River basin.

The "Hehuang area" is adjacent to the Hexi Corridor in the north and the Tubo Dynasty in the south. It can enter the Western Regions through Qinghai Lake and the Qaidam Basin in the west, enter Shaanxi through the Guanlong Road in the east, and enter Bashu through the Qiangdi Road in the southeast.

This region served as the core area for the ancient Qiang people, who spread in all directions through these ancient roads. Some Qiang tribes migrated southward into the heartland of the Qinghai-Tibet Plateau, where they merged with the ethnic groups on the plateau and eventually formed the Tibetan ethnic group. Some Qiang tribes migrated eastward into the Guanzhong area of Shaanxi and assimilated into the Han ethnic group, which is believed to be the origin of the Zhou and Qin dynasties. Some Qiang tribes migrated southward into what is now Sichuan, forming the Qiang ethnic group and numerous Tibeto-Burman ethnic groups in Southwest China. Some Qiang tribes migrated westward, reaching as far as the area around Kucha. Some Qiang tribes migrated northward and reached the area around Ejina in Inner Mongolia.

In 720 AD, The envoy that was sent by the Bugcor Khagan of Turkic Khaganate arrived at Lhasa of Tubo dynasty.

In winter, Tubo army captured the Tang city of Suoge Song (the Tang historical records do not mention this city, and its location cannot be determined).

In the same year, Dashicheng was occupied by Tubo army

In 721 AD, three influential figures in the Tubo Dynasty, including Chief Minister Krizig Zhangnyen and ministers Zhang Tsanto and Zhang Trintsang, passed away. Emperor Tride Zuktsen of Tubo dynasty appointed another minister, Krisumje Tsangzher, as the Chief Minister.

The year 721 AD can be seen as a watershed moment in the rule of the Tubo regime. Prior to 721 AD, the collective leadership of the ministers was prominent, but after 721 AD, Emperor Tride Zuktsen personally governed the state.

In the same year, the Tubo dynasty established the "Red Register" (a military household register) system on the land throughout Tubo kingdom, recording various important documents on wooden slips.

In 722 AD, Tubo broke the alliance with the Tang Dynasty and besieged Bruzha. The Tubo army captured 9 cities of Bruzha. The King of Bruzha urgently sought help from Zhang Xiaosong, the military governor of Beiting. Zhang Xiaosong dispatched Zhang Sili with four thousand elite soldiers to support Bruzha. Together with the King of Bruzha, they launched a counter-attack and defeated the Tubo army. From then on, Tubo's western frontier was cut off from Central Asia, and Tubo's influence was hindered.

In the same year, Tubo began a comprehensive investigation and calculation of the income and expenditure of the Tubo royal family's expenses.

In 723 AD, Emperor Tride Zuktsen of Tubo inspected the northern regions and went hunting, enjoying the capture of wild yaks. At this point, the emperor was gradually maturing and beginning to exercise his power.

In the same year, Emperor Tride Zuktsen of Tubo took up residence in the kingdom of Nipurwa and dismissed the 2 "Ngan pon" which emans the financial officer.

In the same year, in the fourth month of the lunar calendar, the conflict between Tang dynasty and Tubo dynasty reignited. The military governor of Longyou of Tang dynasty launched an attack on Tubo army and sent the captives to Chang'an (now, Xi'an city, Shaan'xi province)as a tribute.

In the same year, in the 10th month of the lunar calendar, an envoy was sent to report, stating, "In May of last year, Princess Jincheng intended to flee to Keshi (present-day Kashmir), and returned to the Tang Dynasty through this route."

In 725 AD, the chief prime minister of Tubo,Krisumje Tsangzher, passed away. Emperor Tride Zuktsen of Tubo ordered to exile Senko Mengchun and appointed Nge Mangzhamta Tsap as the new chief prime minister.

In 726 AD, in winter, the Tubo general, Da Tsakonglo, launched an attack on Dadoud Bagu (Qilian Mountains, Biantoukou Pass) and besieged Ganzhou (now, Zhangye city, Gansu province), burning villages.

The Tang army avoided direct confrontation with the Tubo army and took advantage of heavy snowfall to retreat. Da Tsakonglo led his troops to retreat from Jishijun (Guide County, Qinghai province) to the west. The Tang generals sent troops to burn the grass along the road, and when Da Tsakonglo's army reached Dafeichuan for rest and recuperation, they found that the grass was depleted and more than half of their horses had died. The Tang army followed closely behind, crossing the frozen Qinghai Lake and launching an attack on the Tubo army. At that time, the main force of the Tubo army had already crossed the Dafei Mountain, and only the logistics and exhausted soldiers remained on the lakeside. The Tang generals defeated and plundered the tubo army and returned, which had caused a large loss of Tubo army

In the same year, Tubo dynasty reduced the number of Ngan pon from eight to four and limited the scope of Ngan pon's authority, streamlining certain bloated bureaucratic institutions.

In 727 AD, in the first month of the lunar calendar, the military governor of Liangzhou achieved a great victory over Tubo army in the west of Qinghai.

In the same year, in the ninth month of the lunar calendar, Tubo general Da Tsakonglo and Cogro Mangpoje once again entered Hexi Corridor, capturing Guazhou (now, Guazhou County, Gansu province) and destroying the city. The Tubo army also attacked Suzhou (present-day Jiuquan, Gansu province), Changle town (south of Anxi County, Gansu), and Changmenjun (north of Yumen City, Gansu province). Da Tsakonglo was well-informed about the situation in the Tang Dynasty and attacked Guazhou to plunder the supplies stored by the Tang army, and Tubo army gained significant benefits in this battle.After the "Guazhou battle", the renowned Tubo general Da Tsakonglo entered the Western Regions, specifically the Tarim Basin.

In the ninth month of the lunar calendar, together with the leader of the Turgish tribe, Suluo, they besieged Kucha (Anxi City). Although they were repelled by the Tang army and did not succeed, this expedition by the Tubo army in the Western Regions was quite spectacular. During this time, Tubo dynasty also planned to join forces with the Tujue to attack the Tang army, but the Tujue Khanate's Khagan Pijia (son of Gudulu) handed over Tubo's secret documents to the Tang Dynasty, thwarting the conspiracy. At this time, the relationship between the Tujue Khanate and Tubo dynasty was not as close as before, but the relationship between the Turgish tribe and Tubo remained extraordinary.

In the same year, Emperor Tride Zuktsen of Tubo inspected the Qinghai-Tuyuhun region. According to the "Chronicle of Major Events," the emperor rewarded most of the Tuyuhun officials during his visit. The palace tent of Tride Zuktsen was moved to the Tuyuhun region, which possibly due to the ongoing conflict with the Tang Dynasty, and it also shows the extensive range of the movement of the palace tent.

A Princess of Tubo had married the king of Tuyuhun, and at this time, the king of Tuyuhun was the son of the Tubo princess, so he was called the Nephew - Tuyuhun king.

Shortly after taking office, the new chief prime minister - Nge Mangzhamta Tsap died, and Tride Zuktsen appointed Da Tsakonglo as the new chief prime minister

In 728 AD, in the first month of the lunar calendar, the Deputy Chief Military Governor of Anxi, Zhao Yizhen, defeated Tubo army at Quzicheng.

In the ^7th month of the lunar calendar, Tubo attacked Guazhou, and the Tang army defeated Tubo army at Kebo Valley and Badamo City.

In the 8^th month of the lunar calendar, the Tang generals, Dubeinke, led his troops to defeat Tubo army at Qilian City.

In the same year, Da Tsakonglo was killed for his crimes. Chinese historical records say that this was due to the Tang Dynasty's use of covert tactics. Then after, Tubo dynasty appointed Dro Chungsang Ormang as the new chief prime minister.

In 729 AD, In the 3^rd month of the lunar calendar,General Zhang Shougui of the Tang Dynasty achieved a great victory over Tubo army in the area of present-day Xining. Xin'an king - Li Yi of Tang Dynasty captured Damomen City（now, in the southeast of Gonghe County） and Shibucheng (southwest of Huangyuan County), destroyed the Camel Bridge, and reclaimed over a thousand miles of lost territory. Tubo army was led by Kyesang dongtsab

Note: In the years 728 AD-729 AD, Tubo dynasty suffered consecutive major defeats. Tubo's influence in eastern Qinghai was weakened, so Emperor Tride Zuktsen of Tubo dynasty sent an envoy to negotiate with Tang dynasty for peace. The Tang Dynasty also agreed to negotiate with Tubo due to the strain of continuous military campaigns and the poor living conditions of the people in Hexi Corridor and Longyou region.

In the winter of this year, a Tang envoy named "Li Tsong Kan" entered Tubo for negotiations (this is not recorded in Tang historical records). Emperor Tride Zuktsen was pleased to see the Tang envoy and immediately sent a well-known Tubo diplomat named Men Shina to the Tang Dynasty. Emperor Tride Zuktsen blamed the border generals for the war and expressed his sincere intention for reconciliation, proposing that Tang and Tubo were of the same family.

In 730 AD, in the 5^th month of the lunar calendar, Tubo sent envoys to seek a peace alliance. Tang dynasty accepted, and Emperor Tang Xuanzong ordered Huangfu Weiming and Zhang Yuanfang to go to Lhasa as envoys. In the summer, Tang envoy "Tswa de pu" departed to Lhasa(this envoy was not recorded in Tang historical records).

In the 10^th month of the lunar calendar, Tubo sent diplomat Men Shina with Huangfu Weiming to offer tribute and present a memorial to the Tang Dynasty, requesting to strengthen the treaty of peace and friendship and presenting books and documents. Another treaty was signed, establishing Chi-ling(now, the Sun-Moon Mountain, Qinghai province) as the boundary.

In 731 AD, in the 1^st month of the lunar calendar, Tang Dynasty appointed Cui Lin as the envoy to Tubo. The Tubo envoy reported that Princess Jincheng had requested books such as the "Book of Songs," "Book of Rites," "Zuo Zhuan," etc., from the Tang dynasty. After deliberation, Tang dynasty agreed to provide them.

In the summer, Tang envoy "Cang do shi" went to Lhasa.

In the 9^th month of the lunar calendar, Tubo sent its minister, Lünmingshangtalu, to the Tang Dynasty, proposing mutual trade at Chiling. Later of this year, Tang dynasty and Tubo dynasty began to re-negociate.

Note: After Princess Jincheng married to Tubo king, in the year 731 AD, messengers were sent to the Tang Dynasty to request books such as the "Book of Songs," "Book of Rites," "Zuo Zhuan," and "Wenxuan."

In the Tibetan documents discovered in Dunhuang, there are also translations of traditional Chinese classics, including four sections of the "Book of Documents" and six sections of the "Annals of Spring and Autumn." There is also the "Letter of Confucius to His Nephew Xiangnang," etc. The translations of these works in Tibetan are vivid, fluent, and clear, accurately reflecting the characteristics of the original texts.

In some parts, based on Chinese historical records and legendary stories, there were adaptations. For example, in the story of King Zhou of Shang killing Bigan, the phrase "Xin chao she zhi qiang, pou xian ren zhi xin" was translated into a paragraph in Tibetan, making it understandable to those who are not familiar with Chinese cultural references, reflecting the high cultural cultivation of the translator.

There were definitely more translations at that time, and it's logical to assume that there were Tibetan translations of the "Book of Songs" and others obtained by Princess Jincheng. However, due to the Tubo partition and subsequent long-term wars, many cultural works were not preserved and passed down. But from the existing fragments of translated works, we can see the open cultural policy of the Tubo Dynasty, which was interrupted for a long period afterward, and even the efforts made were forgotten by later generations.

In 732 AD, envoys from the Abbasid Caliphate and Tujue-Qide came to pay tribute to the Tibetan emperor. That same year, the Tang envoy "Li kheng" traveled to Lhasa and the Tang-Tubo alliance was begun to establish

In 733 AD, the Tibetan emperor's palace tent was stationed in the "Dzun" area.

In the same year, Tibet conducted a comprehensive census of the population in the four "Ru (district)" of the Tibetan heartland, indicating that the Tibetan dynasty had a relatively strict household registration system.

During the same year, envoys of Mywa Lakag from Nanzhao kingdom came to Tubo dynasty to pay tribute.

In the 9^th month of the lunar calendar, on the eastern front of Tubo dynasty, the Tang Dynasty and Tubo Dynasty agreed to establish a boundary monument at Chiling (now Sun & Moon Mountain in Qinghai Province) to divide their territories. It was determined that Chiling would be the boundary, and both sides agreed not to invade each other and to maintain friendly relations.

They also established trading markets at Chiling and Gansongling to facilitate trade between the two sides. Border generals from both the Tang Dynasty and Tubo Dynasty, as well as local officials, participated in the meetings. It was announced that both sides should reconcile and prohibit plundering each other. However, this did not bring about lasting peace. Soon after, the Tubo army launched a large-scale attack on the Hexi Corridor, but was defeated by General Wang Zhongsi of the Tang Dynasty.

In the northern region of Tubo, Tubo and the Tujue tribe united and prepared to launch an attack on the Tang Dynasty. In the southeastern region of Tubo, Tubo Dynasty and the Nanzhao Kingdom in Yunnan joined forces, posing a great threat to the southwestern border of the Tang Dynasty.

In 734 AD, in the 1^st month of the lunar calendar, Tibetan envoys came to the Tang Dynasty, and the Tang envoy "Wang do shi" traveled to Tibet to pay tribute.

In the same year, Tibet sent Princess Drolma Lo to marry the Türgesh Khan Suluo. The "Old Book of Tang" also records: "The Türgesh and Tubo also married their daughters to Suluo." This political marriage has caused great alertness in the Tang Dynasty. The Tang Dynasty, in the name of the Tang Emperor, sent a letter to the Tibetan Tubo King, condemning the marriage alliance between Tubo and the Türgesh.

At the same time, the Tubo dynasty began to recruit young men from the Tubyuhun area as soldiers.

In 735 AD, in the 2^nd month of the lunar calendar, Tibetan envoys came to congratulate the Tang Dynasty.

In the 3^rd month of the lunar calendar, the Tang envoy "Jevu jang shi" departed for Tubo dynasty

In 736 AD, in the 1^st month of the lunar calendar, Tubo sent envoys to the Tang Dynasty to present valuable tributes.

In the same year, one of the prominent Tubo ministers, "Coro Mangpoje kyichung," led troops to the Western Turks, preparing to besiege Bruzha.

In the same year, during winter, the Tang envoy named "Li zhang sho" (possibly Li Song) was appointed to visit Tubo.

In 737 AD, in the 2^nd month of the lunar calendar, Tang general Cui Xiyi and Tibetan general Krizig Zhangnyen made a vow of withdrawing border defense forces to facilitate grazing.

However, Tubo dynasty once again broke the alliance with the Tang Dynasty and besieged Bruzha. The Tibetan general "Lonkye Zangdongtsab" led troops to attack Bruzha from the west. Bruzha sought help from the Tang Dynasty, and the Tang Dynasty ordered Tubo dynasty to withdraw its troops. However, Tubo dynasty refused and successfully captured Bruzha. King Su Shili of Bruzha surrendered to Tubo forces, and Tubo dynasty once again opened up the route to Central Asia, achieving a major victory. Over twenty countries in the Pamir region submitted to Tubo dynasty.

In the same year, in retaliation for the Tang Dynasty's request for Tubo Dynasty to stop attacking Bruzha, Tang general Cui Xiyi was ordered to lead troops to launch a surprise attack on Tubo army from the west of Qinghai. Tubo army suffered a major defeat, and Krizig Zhangnyen fled. Both the Tang Dynasty and Tubo Dynasty blamed each other for breaking the alliance.

In 738 AD, in the 3^rd month of the lunar calendar, Tubo army launched an attack on Hexi Corridor but was repelled by the troops led by general Cui Xiyi of Tang dynasty, moreover, the Tang general Du Xiwang led an army to attack and capture the newly built Tibetan castle, and renaming it Weirongjun (Men Yuan County, Qinghai).

In the 6^th month of the lunar calendar, the stone stele in Chiling was also overturned by the Tang army, leading to Tubo's cessation of tribute and the severing of diplomatic relations between Tang and Tubo. From this point on, Tang dynasty and Tubo dynasty started a comprehensive confrontation, engaging in fierce battles in Qinghai, Central Asia, the Pamir region, Yunnan, and other border areas. The conflict reached a stalemate with victories and defeats on both sides.

In the 7^th month of the lunar calendar, Tang general Du Xiwang attempted to seize the Tibetan's river bridge and constructed Yanchuan city (Xunhua County, Qinghai) near the river. Tibet sent troops to launch attacks but failed, and Tang army stationed in Yanchuan called "Zhen Xi troop".

In the southern region of Tubo, the Kingdom of Nanzhao bribed "Wang Yu" --the newly appointed Tang local chief, and requested the consolidation of the "Six Zhao" into one. With his support, Wang Yu planned to use Nanzhao's forces to attack the Tibetan-occupied Anrong city (Now, Mao county of Sichuan province). Anrong was one of the strategically important sites fiercely contested by Tubo army and Tang army in the southwest region. The power of Nanzhao kingdom continued to grow, gradually incorporating the territories of the Six Zhao and establishing Dali as its political center (located in the southern Taihe Village in present-day Dali, Yunnan). Nanzhao attacked Shilangzhao, and later, Nanzhao captured Jianchuan (Jianchuan, Yunnan) in the sphere of Tibetan influence, and the king of Shilangzhao, "Qianpang Luodian," sought refuge in Tubo dynasty. Due to the successful capture of Jianchuan, the Tang granted Nanzhao's Pi Luoge the title of King of Yunnan, eventually leading to the establishment of the Kingdom of Nanzhao.

At this time, Nanzhao had become a vassal of the Tang dynasty, but Anrong city remained in Tibetan hands, and the struggle for Anrong city often affected the regional situation.

In the 9^th month of the lunar calendar, Wang Yu, the chief of Jiannan Dao, waged war against Tubo force at Anrong city, but Tibetan reinforcements swiftly arrived, resulting in a great defeat for Tang and heavy casualties.

In 739 AD, amidst the ongoing conflict between the Tang and Tubo dynasty, Princess Jin Cheng passed away.

In the 8^th month of the lunar calendar, Tibet launched attacks on Baishuijun (northwest of Datong County, Qinghai province) and Anrenjun (northwest of Huangyuan County, Qinghai province). The Tibetan army suffered significant losses, and the Tang achieved a major victory over Tubo army in Shanzhou (present-day Xining, Huangzhoong, Qinghai province).

During the same year, Tride Zuktsen inspected the "Bi" region, while his son, Prince "Laben," passed away in the "Dzun" region.

In the same year, Tride Zuktsen began to promote Buddhism. He sent people to India to seek Buddhist teachings, dispatched envoys to the Kailash Mountain to retrieve several Buddhist scriptures, and built five temples to house and worship these scriptures. He invited translators to translate Buddhist scriptures, and translated the Chinese texts "The Golden Light Sutra of the Most Victorious Mahayana" and "Vinaya Separates," into Tibetan. He also built the Guazhou monastery in the vicinity of Samye Monastery, located about three miles north of the Yarlung Tsangpo River in the area of Red Rock (Brag dmar), and also built temples in Qingpu.

Tride Zuktsen also brought back a group of Buddhist monks who had been expelled from the Kingdom of Khotan from Tshal byi (located on the southern edge of the Tarim Basin) and built seven major monasteries in Lhasa to support these monks. As a result, Buddhist activities within the Tibetan Empire increased significantly.

Due to Tride Zuktsen's devoted efforts in promoting Buddhism, it aroused suspicion and fear among the nobles and ministers who adhered to the native religion of Bon.

In 740 AD, in order to strengthen control over Bruzha, Tubo employed a marriage alliance. Tubo's princess, Chimalu (the elder sister of Tubo King Tride Zuktsen), married the king of Bruzha, Su Shili, bringing the Pamir region under Tubo's influence. The Tang Dynasty protested against Tubo's occupation of Bruzha.

In the same year, an epidemic outbreak occurred in Tubo, resulting in a large number of deaths. The epidemic continued until the following year (741 AD) before finally coming to an end.

In the 3^rd lunar month, General Zhangqiu Jianqiong, the military governor of Jiannan of Tang Dynasty, recaptured Anrong City (now Mao County, Sichuan province) from Tubo's control and stationed troops to defend this city.

In the 6^th lunar month, Tubo forces launched a siege on Anrong City but were repelled by the Tang army.

In the 9^th lunar month, Tubo forces once again besieged Anrong City and Weizhou (now, Lixian County, Sichuan province), but were once again defeated by the Tang army. At this time, the Tang Dynasty changed the name of Anrong City to "Pingrong City".

In the 12^th month of the lunar calendar, Tubo sent envoys to inform about the death of Princess Jincheng and requested a peace treaty with the Tang Dynasty. However, Emperor Tang Xuanzong refused Tubo's request for peace.

In 741 AD, Tride Zuktsen once again went on a tour of border defense for the purpose of strengthening the management of the border territories.

In the 6^th month of the lunar calendar, according to the "Book of Tang" (Volume 214), Tubo's army of 400,000 launched an attack on Anren Jun but was repelled by the Tang army.

In the 12^th month of the lunar calendar, Tubo occupied Dahua County (located to the northwest of Jianzha County, and East of Guide county), committed massacres, and defeated Tang general Gai Jiayun, and captured Shibu castle

Furthermore, during the two-year-long epidemic, the Tibetan nobles of the Bon religion took the opportunity to retaliate, falsely blaming Buddhism as a heterodox foreign religion and angering the Bon deities, which led to the outbreak of the disaster. As a result, all foreign monks were expelled from Tubo dynasty, and the Buddhist religious movement was also hindered.

[Shibu castle]

Shibu castle located in the present-day Sun-moon Township, Huangyuan County, southwest of Xining. It was situated in a strategic location which is the throat area between the Sun-moon Mountain Pass and the Yanshui River Valley on the ancient Tang-Tubo Road, at an elevation of approximately 3600 meters.

Shibu castle was an important transportation hub between Qinghai Lake and the Huang River Basin, with steep cliffs on three sides and a slope on the northern side allowing the only access to the mountaintop via a mountain valley, making it a formidable defensive position. The functionality of Shibucheng lies in its ability to observe from a high vantage point, transmit information, and defend its position with the advantage of its natural fortifications. It provides a commanding view of the two roads leading northeast and east from the Sun-moon Mountain Pass, making it a crucial contested high point for the Tang and Tubo dynasties.

In 742 AD, one of the sons of Tride Zuktsen, named Langzhi Du, died in battle. Another son of Tride Zuktsen was born in the "Dramar" region.

In the summer of the same year, Tang envoy "An Dalang" came to visit Tubo dynasty, and Uman envoy Ropi Yi visited the Tubo Dynasty to pay their respects.

In the same year, Tubo general Mangpoje led a large-scale attack on Heyuanjun (located within the territory of Duzhou, near present-day Xining).

In the 12^th month of the lunar calendar, Tang generals Huangfu Weiming and Wang Cui led their troops to a major victory against the Tubo army at Dalin

In 743 AD, in the 2^nd month of the lunar calendar, Tang general Huangfu Weiming continued his westward campaign, capturing the city of Hongji in Dahua County. The Tang army then approached the vicinity of Shibu castle, where the Tang and Tubo forces engaged in a fierce battle for control.

In the 4^th month of the lunar calendar, the Tang army captured the city of Hongji (west of Kuozhou, now west of Guide, Qinghai province).

In this winter, Tang envoy "Kwa cung lang " went to the Tubo dynasty

In 744 AD, Tang envoy "Cang Ywan Ve" went to the Tubo dynasty, and in the same year, the Türgesh envoy went to the Tubo dynasty

Tubo dynasty began to take inventory of the military conscription registers from various regions and transferred the imperial decree from the "Red registers" to "Yellow paper registers".

Papermaking technology was introduced to Tubo from the Tang Dynasty during the reign of Songtsen Gampo. This record in the "Dashi Ji Nian" is the earliest evidence we have of Tubo's use of paper.

In the same year, Bal Dongtsab and Dro Chungsang jointly presided over the winter assembly and formulated regulations for the management of the farming and herding areas of the 4 "Ru".

In 745 AD, Tride Zuktsen removed Shang Zhegong and Sengge Penglajie from their positions as ministers.

In the 9^th month of the lunar calendar, Tang general Huangfu Weiming launched an attack and attempted to recapture Shibu castle (now, in the Huangyuan County, Qinghai province), but suffered heavy losses and was defeated by Tubo army.

In 746 AD, Tride Zuktsen ordered separate treatment for the settlers involved in reclaiming the land in Dongdai (Qianhu), and issued a decree to instruct officials at all levels to reduce the taxes owed by the common people.

In 747 AD, Tride Zuktsen led his ministers to formulate various systems for dividing the agricultural and pastoral areas. The Tubo king Tride Zuktsen finally consolidated the position of the royal family and exercised the power of the king of Tubo. His series of successful domestic policies helped the Tubo Kingdom to advance towards greater strength.

In the same year, Emperor Tang Xuanzong of Tang ordered Vice Protector General Gao Xianzhi (a Goryeo person) to lead troops to attack Bruzha. Gao Xianzhi organized an expeditionary force of over ten thousand elite infantry and cavalry, starting from "Anxi", and after several months of arduous journey, they first captured Tubo's "Lianfang Fort". Then after, they launched a sudden attack on Bruzha, capturing the king and Tubo princess, and cutting off the Po Yi River vine bridge that Tubo's army had to pass through, a bridge that would take a year to repair.

When Tubo's reinforcements hastily arrived, they could only watch from across the river. The details of Gao Xianzhi's remarkable expedition are recorded in the Biographies of Gao Xianzhi in both the "Old and New Tang Histories". Tang renamed Bruzha as "Guiren" and established the Guiren Army, enlisting a thousand soldiers to garrison it. Su Shili and his wife (Tride Zuktsen's sister, Drolma Lo) were brought to Tang dynasty's capital -- Chang'an, where the Tang Dynasty appointed Su Shili as Right Sustainer General. Gao Xianzhi's victory shocked the Central Asian countries caught in the middle of great powers, and Tubo's expansion in Central Asia was setback.

In the same year, Emperor Tang Xuanzong of Tang dynasty wanted Hexi and Longyou Jiedushi Wang Zhongsu to attack and recapture Shibu catsle (now, in the Huangyuan County, Qinghai province), but Wang Zhongsu did not agree to take the Shibu catsle. However, Tang general Dong Yanguang voluntarily requested to attack Shibu castle, but the attack was unsuccessful and they were defeated by the Tubo army.

In 748 AD, Ge Shuhan, who took over Wang Zhongsi as the military governor of Longyou, built the Shenwei Army in Qinghai and established Yinglong City on Longju Island in Qinghai Lake (Island Hai Xinshan in Qinghai Lake), effectively blocking the Tubo army's attack.

In 749 AD, Tang general Ge Shuhan, the military governor of Longyou, led a force of sixty thousand soldiers to attack Shibu Castle (now, in the Huangyuan County, Qinghai province). Shibu Castle was strategically located with three impassable sides and only one road for passage. Tubo defended the city with only a few hundred soldiers, using rolling logs and stones to block the Tang army's advance.

Tang army's attack lasted for several days without success, and the war was extremely brutal. It was only with the sacrifice of tens of thousands of Tang soldiers that Shibu castle was finally captured, and over four hundred Tubo soldiers were captured.

Ge Shuhan then ordered two thousand soldiers to garrison Longju Island in Qinghai Lake, and Tang established Zhenwu Army at Shibu castle. From then on, the line of Hehuang area was under Ge Shuhan's energetic management, putting Tubo on the defensive.

In 750 AD, Tang general Gao Xianzhi launched an offensive in Central Asia, capturing the pro-Tubo Jieshi Kingdom, capturing its king, Bote Mei, and capturing the Khan of Türgesh

In the same year, Tang general Wang Nande led his army to launch an attack on Tubo's eastern front, attacking and capturing Wuqiao, Shuodun City (west of Kuozhou, southeastern of Gonghe County).

In 751 AD, In the year 751 AD, the Abbasid (Arab) dynasty and the Tibetan Empire formed a coalition and defeated the Tang army led by General Gao Xianzhi in the Battle of Talas. This was a significant failure for the Tang Dynasty in the Central Asian, marking the end of Tang Dynasty's westward expansion and the replacement of Tang Dynasty's influence by the Tibetan Empire.

In the same year, Yang Guozhong, the military governor of Xichuan of the Tang Dynasty, sent Xian Yu Zhongtong with an army of 80,000 to attack Rongzhou (Now, Yibin city, Sichuan province)and Xizhou(Now, Xichang city, Sichuan province), launching a three-pronged campaign to conquer Nanzhao kingdom. Nanzhao suffered consecutive defeats, and its king, Ge Luo Feng, sent envoys to apologize to the Tang Dynasty, requesting the return of plundered goods and seeking reconciliation. Otherwise, they threatened to surrender to the Tibetan Empire, but the Tang Dynasty refused. In response, Nanzhao kingdom sought assistance from the Tibetan Empire, and the Tibetan general, Lun Rotsan, suggested sending troops to help.

The Tang army advanced towards the Nanzhao capital of Taihe castle and engaged in battle with the Nanzhao army, which was supported by the Tibetan Empire by then. In this battle, the Tang army suffered a major defeat, with an estimated 60,000 Tang soldiers killed. From this point on, the Tang Dynasty completely severed ties with the Kingdom of Nanzhao, while the relationship between Nanzhao and the Tibetan Empire grew closer. After defeating the Tang general Xian Yu Zhongtong, Nanzhao Kingdom sent envoys westward to Lhasa to present valuable gifts and pay tribute.

In 752 AD, King Ge Luo Feng of Nanzhao kingdom submitted to Tubo Dynasty, and Tubo dynasty called him "Tsanpo Cung" ("Cung" meaning "younger brother, "Tsanpo Cung" means the yunger brother of the Tsanpo"). Ge Luo Feng of Nanzhao kingdom said, "Although life begins with misfortune, death is end with resentment. How can we forget the great ceremony despite past grievances?" He built the "Tang Tianbao Warriors Tomb" (commonly known as the Ten Thousand Soldiers Tomb) and erected the Nanzhao Dehua Stele in the capital city of Taihe, inscribed with words such as "Rebellion against Tang dynasty was inevitable."

Note: Nanzhao's submission to Tubo dynasty was the greatest success in Tride Zuktsen's external operations. Tubo dynasty attached great importance to this event, granting Nanzhao's king a golden seal with the title "Eastern Emperor." Tubo dynasty sent its prime minister to conduct a grand enthronement ceremony for the king and officials of Nanzhao kingdom. Tubo dynasty not only enfeoffed the Nanzhao king but also conferred titles to the officials and bestowed imperial edicts, gold, silver, and treasures. Since then, Nanzhao used the reign title of "Tsanpo Cung", and Tubo dynasty and Nanzhao kingdom had frequent political, economic, and cultural exchanges.

Note: After the standoff between the Tang Dynasty and Tubo Dynasty, Tubo dynasty has already taken control of the areas including the Western Regions, Pamir Plateau, Yunnan, and other regions that were previously under the control of the Tang Dynasty.

In 753 AD, on the southern front of Tubo Dynasty, the Tang Dynasty reestablished the "Yaozhou Prefecture（Nowadays,Yao’an county, Yunnan province)," with Jia Guan as the commander. General Hong Guangcheng of the Nanzhao Kingdom, and Tubo's Lun Krizig Zhangnyen joined forces to besiege the city of Yaozhou Prefecture. As a result, Commander Jia Guan was captured, and the soldiers were driven out.

In the same year, on the northwest front of Tubo dynasty, the Tang Dynasty sent troops to suppress Bruzha, which remained under Tubo's rule. The situation in Central Asia, contested by the Tang Dynasty, Tubo Dynasty, and the Abbasid Caliphate, remained unchanged at this time.

In the same year, on the eastern front of Tubo Dynasty, Tang General Ge Shuhan led his troops to attack Tubo army. The Tang army once again captured cities such as Hongji and Damosi (now in the southeast of Gonghe county, Qinghai Province) and occupied the Nine Curved area. The following year, in the Nine Curved area, the Tubo army was completely expelled from the upper reaches of the Yellow River. The Tang Dynasty regained control of the Nine Curved tribe (corresponding to the western part of Kuozhou) from Tubo and established the Tiaotao and Jiaohe counties and the Shence Army there.

In 754 AD, the Tang Dynasty sent General Li Fu with a hundred thousand troops to attack the Nanzhao Kingdom. Tubo General Lun Krizig Zhangnyen led a Tubo army to support Nanzhao army, and Tubo and Nanzhao once again defeated the Tang army in joint action, resulting in the drowning of the Tang army's commander, Li Fu. After this battle, for a long time, Tubo maintained superiority in the Yunnan region.

In the same year, the Tubo King Tride Zuktsen was assassinated, and his thirteen-year-old son, Trisong Detsen, succeeded him.

Note: [Regarding the Assassination of Tride Zuktsen]

In 754 AD, the Tubo King, Tride Zuktsen, was suspected to have been assassinated by the Prime Minister, Bal Dongtsab, and Lang Mezig.

The "Zizhi Tongjian" (Volume 217) records, "In the spring of 755 AD, in the 1st month of the lunar calendar, the son of the King of Subi(Supa) kingdom, Xinuo Luo, left Tubo dynasty and surrendered to the Tang Dynasty." Later, the Tang Dynasty conferred the title of Prince Huaiyi on Xinuo Luo and gave him the name Li Zhongxin. The surrender of Xinuo Luo to the Tang Dynasty occurred in the first month of the fourteenth year of the Tianbao reign (755 AD), so it is likely that he surrendered to the Tang Dynasty at the end of the thirteenth year of the Tianbao reign (754 AD). Thus, the assassination of Tride Zuktsen and the surrender of Xinuo Luo to the Tang Dynasty likely happened around the same time and are closely related.

In the Tubo historical document "Record of the Major events" unearthed in Dunhuang, it states, "[Until the Year of the Sheep] (the fourteenth year of the Tianbao reign, 755 AD)... the soldiers captured a group of attendants who attempted to assassinate the king. The slaves of the Lang and Mo clans were expelled... and the confiscated properties of the convicted Lang and Mo clans were seized."

Lang refers to Lang Mezig, and Mo refers to Bal Dongtsab, both of whom were powerful officials during the reign of Tride Zuktsen

Based on the current historical records, the assassination of Tride Zuktsen was a carefully organized conspiracy with a complex background. It was not merely a struggle between the nobility and the royal family but also involved acts of rebellion, such as Su Bi's rebellious

In 755 AD, Tubo Dynasty executed Bal Dongtsab and Lang Mezig, and killed the King of Subi(Sunpa) kingdom that lead the escape of his son Xinuo Luo to the Tang Dynasty. Xinuo Luo was granted the title of Prince Huaiyi by the Tang Dynasty. The Tubo dynasty dispatched troops to suppress the rebellion within Tubo territory.

In the same year, Chisong Dezan ascended to the throne as the new king. However, in this year, the Tang Dynasty experienced the "Anshi Rebellion," causing Emperor Tang Xuanzong of the Tang Dynasty to flee the capital Chang'an (now Xi'an, Shaan'xi province) for refuge. The Tang Dynasty mobilized a large number of troops from the northwest and other regions that were originally stationed to deal with Tubo army to suppress the rebellion, leaving the western defense of the Tang Dynasty vulnerable. Taking advantage of the internal turmoil in the Tang Dynasty, the Tubo Kingdom launched a fully organized and planned military campaign in its eastern front, occupying large areas that were originally under the control of the Tang Dynasty, such as Longyou region, Hexi Corridor, and Anxi Four Garrison.

In the same year, Nganlam Takdra Lukhong was granted the title of Marshal (Magpon) after capturing Taozhou (now, Lintan County, Gansu province) and other places.

In the same year, Tubo king appointed Lun Krizang and Zhang Tongtsan as the Prime Ministers, whom led the army to capture Jizhou City and recapture the military town of Hongzhou in the Yellow River Basin.

In the same year, the Tubo king appointed Lun kri Dratagtse, Lun Mangtsan Pangang, and Lun Dozher as Prime Ministers to oversee the Duomai summer meeting; and to appoint Chi Zhanggyal Zigshuteng as the Prime Minister to oversee the winter meeting

In the same year, the priminister Chi Zhanggyal Zigshuteng was tasked with confiscating the properties of the rebellious ministers Lang family and Bal family.

In 756 AD, Trisong Detsen was officially enthroned and began his reign.

At the same time, in the southern front of Tubo Dynasty, Trisong Detsen sent envoys to the king of Nanzhao kingdom, Ge Luofeng, issuing an edict requesting the cooperation of Nanzhao's army in launching an attack on Tang Dynasty. The Tubo and Nanzhao allied forces launched a joint attack on Yuegui and Huitong. The local Tang Dynasty commander in Yuegui resisted, but the Tubo and Nanzhao forces eventually captured Yuegui, Jiu Prefecture (now Xichang, Sichaun province), and other areas. The Huitong defenders surrendered without fighting under the offensive pressure of the Nanzhao and Tubo allied forces.

In the same year, the Tubo king appointed Lun Kyezang Gyakong to oversee the summer meeting

In the 8^th month of lunar calendar, Tubo dynasty sent envoys to Tang dynasty requesting to assist of helping in suppressing the "Anshi Rebellion." The Tang Dynasty rejected Tubo's request, but Tubo dynasty gained further understanding of the situation in the Tang Dynasty through its envoys. Subsequently, Tubo launched an attack on the Tang Dynasty's territory. In the eastern front, Tubo army and Nanzhao army captured the cities of Secu, Tseci, Shibu castle, Baigu castle (southwest of Guide County, Qinghai), and Diaokong castle (in present-day Tongren County, Qinghai).

In the same year, Tubo dynasty gradually restored its prestige in the Pamir region. From this year to 760 AD, envoys from small countries in the upper region, such as Pujianabo, Kuowei, and Shinie, came to pay tribute. The Tubo dynasty appointed Bagoer Nando and Jie Nangzan as envoys to visit and establish diplomatic relations.

Note: The mentioned "Pujianabo," "Kuowei," "Shinie," likely refer to various countries along the upper reaches of the Amu River, including the Pangzhe River and Humi River basins. According to the "New Book of Tang • Western Regions" (Volume 216), "nine thousand li southeast of the capital, five li east of the Congling garrison, three hundred li south belonging to Humi, and five hundred li northwest reaching Jumi." Tubo dynasty referred to these regions as the "upper region." The frequent interactions between Tubo dynasty and these regions indicate that Tubo reestablished control over the Bruzha Road, and Pamir and other areas became part of Tubo's sphere of influence.

In 757 AD, in the 2^nd month of lunar calendar, Tubo dynasty once again sent envoys to Tang Dynasty requesting to assist in suppressing the rebels. However, Tubo minister Nang Zerlatsan led Tubo army to capture Gya Khartsongka and Linjue castle.

In the 10^th month of lunar calendar, Tubo minister Nang Zerlatsan led Tubo troops to capture Xiping town (also known as Shanzhou, Ledu County in Qinghai province).

In the same year, the Tang Dynasty reestablished Yuegui county, appointing Yang Tingjun as the commander, and Trisong Detsen sent envoys to Nanzhao kingdom requesting their troops to once again occupy Yuegui county of Tang Dynasty. Nanzhao kingdom then sent troops to attack and recapture Yuegui county. It is evident that Nanzhao regime participated in military actions according to Tubo's wishes, and both sides coordinated their efforts.

In 758 AD, Lun Krizang and Lun Kyesang Tagnang, along with others, led their troops to march towards Guzang Liangzhou and captured Heyuanjun (near Xining, Qinghai, belonging to Shanzhou).

In 759 AD, Tubo military commanders Lun Krizang, Zhang Tongtsan and Zhang Tsan ba led their troops to capture Tsongka Chungu.

In 760 AD, Tubo army captured the Shence Army and Kuozhou (approximately present-day Guide county and Hualong county in Qinghai)

In 761 AD, Tubo dynasty took advantage of the Tang Dynasty's vulnerability due to the "Anshi Rebellion", which was from 755 AD to 761 AD, for a period of 7 years, Tubo army launched multiple military campaigns along the Tang-Tubo border.

According to the "Chronicle of Major Events," Lun Kyezang Tanang led Tubo troops captured the cities of Bago and Jiaohu in Liangzhou. Zhang Tongtsan led his troops captured Songzhou (now, Songpan county, Sichuan province) and Zangkar region. At the same time, Tubo ministers such as Nangzhe Zutsan, Lun Krizang, and Zhang Tsanba were busy with military campaigns in the border area between Tubo Dynasty and the Tang Dynasty, spanning from north to south for thousands of miles. This included Liangzhou, Little Zangskar (upper reaches of the Huangshui River, present-day Huangyuan county), The Zongka (lower reaches of the Huangshui River, (present-day Ledu district), Linhong castle, Hongzhou, Xuzhou (present-day Xichang, Sichuan province), and other places.

Since almost all ministers of Tubo dynasty were to focus on invading Tang dynasty, naturally，Tubo dynasty was unable to focus on its internal affairs, and Tubo king, Trisong Detsen, took advantage of this opportunity to abolish the ban on Buddhism and invited "Zhi Bavi Tso" to propagate Buddhism in Tubo dynasty, achieving the initial goal of coexistence of Buddhism and Bon religion. From a political perspective, it also meant that Trisong Detsen could act according to his own will without being restrained by the ministers.

In 762 AD, in the 1^st month of lunar calendar, Tubo dynasty once again sent envoys to the Tang Dynasty for a peace treaty. The Tang Dynasty and the Tibetan Kingdom held the meetings for twice at Guangzhai Temple and Honglong Temple in Chang'an City (now Xi'an, Shaan'xi Province), known as the "Baoying Alliance Oath".

In order to concentrate military forces and suppress the "An Lushan Rebellion," Emperor Tang Suzong of the Tang Dynasty accepted the conditions proposed by Tubo dynasty, which included offering 50,000 pieces of silk and satin annually to Tubo, as well as recognizing Tubo's sovereignty over the territories captured and occupied by Tubo army within the Tang Dynasty in exchange for peace

In summer, a Tang envoy named "Yang doshi" was sent to Tubo dynasty. Soon after, the Tibetan Kingdom implemented a strategic plan to attack and capture Chang'an from the west. The main commander and planner of this operation was a Tibetan general named "Nganlam Takdra Lukhong", known as Ma Chongying in Chinese historical records.

In the 8^th month of the lunar calendar, the Tibetan army captured several places, including Lintao, Chengzhou, and Hezhou.

In winter, the Tubo Dynasty distributed silk and satin from the annual tribute of the Tang Dynasty to officials of the rank of Thousand Household Chief and above.

Note: The peace proposals put forward by the Tubo Dynasty were merely superficial. While the Tubo army was continuously gaining victories, capturing cities and territories, they repeatedly proposed peace talks to the Tang Dynasty. Their aim was to deceive and lull the Tang Dynasty, concealing their larger actions. Each time Tubo envoys entered the Tang Dynasty, it provided them with an opportunity to gather military and internal information of Tang dynasty. General Guo Ziyi of the Tang Dynasty was aware of Tubo's intentions and once advised Emperor of Tang Dynasty that, "We must not underestimate Tubo and the Tangut. We should prepare for them in advance.Tubo's peace proposals were purely meant to thoroughly deceive the Tang Dynasty, allowing them to mobilize troops and make military arrangements."

In 763 AD, Emperor Tang Dezong of Tang Dynasty ascended to the throne in the 1^st month of the lunar calendar. In the 4^th month of the lunar calendar of the same year, he dispatched Li Zhifang, the Imperial Attendant for Cavalry Action, and the Left Academician Cui Lun as envoys to the Tibetan Empire. They were sent to negotiate with the Tubo kingdom regarding the improper request for "annual tribute" and "presenting land maps" during the ""Baoying Alliance", but both envoys and their entourage were detained by the Tubo kingdom

Tubo's military forces were even more formidable, unstoppable like a bamboo breaking through, and in a short period of time, they swiftly captured various cities and regions in the Longyou area, including Lanzhou, Hezhou, Taozhou, Minzhou (Min County, Gansu), Qinzhou (Tianshui city, Gansu), Chengzhou, and Weizhou.

Tubo king, Trisong Detsen, appointed Zhang Gya Zigshuteng and Nganlam Takdra Lukhong as the commanding generals, leading an army of approximately 200,000 troops to move eastward, crossing the Tang-Tubo border and attacking the Tang Dynasty.

In the 7^th month of the lunar calendar, Tubo invaded and captured Dazheng Pass (west of Long County, Shaanxi) of Tang dynasty, causing the entire Longyou region to fall, and the Tubo army directly advanced towards Chang'an, the capital of the Tang Dynasty.

In the 10^th month of the lunar calendar, Tubo attacked Jingzhou (now, north of Jingchuan County, Gansu province), which the governor Gao Hui surrendered and served as a guide for the Tubo army, leading them to break through Binzhou (present-day Binxian County, Shaanxi), and continue attacking Fengtian (now Qian County, Shaanxi) and Wugong (northwest of Wugong County, Shaanxi). Emperor Tang Dezong of Tang dynasty issued an imperial decree to resist Tubo army, but it was too late. Originally, the Tang Dynasty had annexed the Dangxiang and Tuyuhun tribes and settled them in the northwest region. However, these tribes eventually sided with the Tibetan army and participated in the attack launched by the Tibetan army on the Tang Dynasty's capital, Chang'an.

On the 6^th day of the 10^th month of the lunar calendar, the Tubo army crossed the Wei River and reached the city of Chang'an. On the 7^th day of the 10^th month of the lunar calendar, Emperor Tang Dezong of Tang Dynasty fled from Chang'an to Shanzhou to seek refuge.

Chang'an was occupied

According to the "Zizhi Tongjian" (Volume 222), "Officials hid and fled, and the six armies scattered." In the winter of 763 AD, on the 9^th day of the 10^th month of the lunar calendar, without encountering any resistance, the Tubo army entered the city of Chang'an, the largest city in the world at that time. They withdrew from Chang'an on the 21^st day of the 10^th month of the lunar calendar, lasting 13 days. This was the most glorious time in Tubo's military history, capturing the capital of the Tang Dynasty.

During the 13 days of occupying Chang'an, Tubo army established a puppet regime of Tang dynasty

The prosperous city of Chang'an amazed the Tubo people, and they looted extensively while also recruiting various craftsmen that Tubo desperately needed. Chang'an suffered a great disaster. After establishing a pro-Tubo regime, the Tubo army quickly retreated westwards with their spoils. Soon after, the Tang Dynasty's rulers and officials returned to their capital. Without military support and social foundation, the puppet regime built by Tubo army collapsed.

In the 11^th month of the lunar calendar, the Tubo army failed to conquer Fengxiang (Fengxiang County, Shaanxi province). They stationed their troops in places such as Yuanzhou (now, Guyuan county, Ningxia province), Huizhou (now, Jingyuan County, Gansu province), Chengzhou (now, southwest of Lixian County, Gansu province), and Weizhou (present-day Weinan, Shaanxi province), occupying advantageous positions and continued to threaten the Tang Dynasty. The Tubo army's lightning-fast success pushed the battlefield between Tang and Tubo from eastern Qinghai to the Gansu-Shaanxi-Ningxia region. From then on, the Tubo army could directly threaten the heart of the Tang Dynasty and sever the connection between the Tang Dynasty and the Hexi Corridor and the Western Regions.

Tubo continuously launched attacks and harassment near Chang'an, leaving the Tang Dynasty with no time to attend to the Hexi Corridor and Western Regions. Tubo gradually captured the various towns in the Hexi Corridor that were still controlled by Tang Dynasty officials. Therefore, Tubo implemented a strategy of directly attacking Chang'an, pushing their expansion in the eastern region to a high point.

Meanwhile, in the 12^th month of the lunar calendar, on the southern front of Tubo dynasty, in the southwest of the Tang Dynasty, another group of Tubo soldiers captured Song zhou (now, Songpan county, Sichuan province), Wei zhou, and Baozhou (north of Lixian County, Sichuan) and other cities. Among them, Weizhou (now Zagunao Town, Lixian County, Sichuan province) was a military and transportation fortress and a crucial passage for Han forces to support Song zhou from the north. Tubo had previously launched multiple unsuccessful attacks on Weizhou, but this time they succeeded in one fell swoop. Faced with Tubo's offensive, Gao Shi, the military governor of Sichuan, was unable to provide assistance, and subsequently, the Tang-controlled regions of Jiannan and Xishan were also occupied by Tubo.

In this year, Lun Krizang Yabla was appointed as the Chief Prime Minister (Dalun) by the Tubo King Trisong Detsen

In this year, the foundation of the Samye monastery was laid.

Note: Tubo dynasty put a lot of effort into capturing Weizhou. The "Old Book of Tang, Geographical Records" records a story that Tubo sent a woman to marry a soldier guarding the gate of Weizhou. This Tubo female spy gave birth to two boys, whom she raised and educated well. Twenty years later, when the Tubo army attacked the city, the two brothers opened the city gate secretly, allowing the Tubo army to enter. After Tubo captured Weizhou, they renamed it "Wuyou City (meaning Worry-free city)," making it one of the focal points of contention between Tang dynasty and Tubo dynasty

Note: During the reign of Trisong Detsen, the Tubo Kingdom expanded its territory significantly. It extended eastward, roughly with the Long Mountains as the boundary with the Tang Dynasty. Tubo even reached Baoji town several times, threatening Chang'an. To the north, it bordered the Huihu Kingdom in Helan Mountain, Ningxia. To the south, it had Nanzhao kingdom as its vassal state, and to the west, it had the Anxi Four Garrison. In Central Asia, it resisted the Islamic Abbasid Caliphate's army.

In 764 AD, in the 8^th month of the lunar calendar, Tubo dispatched an army of approximately 70,000 soldiers and allied forces from the Huihe tribe to invade the Tang Dynasty. They attacked Liangzhou, Jingzhou, and Binzhou, and then advanced towards Fengtian and Liquan. The capital of the Tang Dynasty was shaken, and martial law was imposed in the capital. However, the Tang army was well-prepared and heavily guarded, making it impossible for the Tubo forces to achieve victory. They had no choice but to retreat across the Jing River. But Tubo later launched a counterattack on Liangzhou and captured the city. Yang Zhilie, the military governor of Hexi, evacuated from Liangzhou to Ganzhou. From then on, the Tang Dynasty's control in Hexi corridor was only maintained in some areas.

In the same year, on the southern front of Tubo dynasty, Yan Wu, the military governor of Jiannan of Tang dynasty, led his troops to defeat the Tubo army and captured Dangou City (likely located in Lixian County, Sichuan).

In the 10^th month of the lunar calendar, Tang general Yan Wu captured the Tubo city of Yanchuan. Yan Wu implemented strict policies in the Jiannan region, but maintained discipline in the military, making it difficult for the Tubo army to break through. From this year onwards, Tubo frequently found itself at a disadvantage in the battles against the Tang Dynasty in the southwestern region.

In 765 AD, Tubo sent envoys to the Tang Dynasty to request peace negotiations.

In the 3^rd month of the lunar calendar, Emperor Tang Daizong ordered Yuan Zai, Du Hongjian, and the Tubo envoy to hold a meeting at Xing Tang Temple, known as the "Yongtai Meeting." The historical records do not specify the content of this meeting, but General Guo Ziyi of Tang Dynasty commented on Tubo's intentions, saying, "Tubo benefits from catching us unprepared. If they come without us being prepared, our country will be undefendable." The Tubo's request of alliance meeting was merely a superficial display, hiding their motives for war.

In the 9^th month of the lunar calendar, Tubo forces, led by Prime Minister Chimzhang Gyalzig Shuteng, the Dongdao Military Governor Zhang Tsanba, Zhang Tongtsan, and Nganlam Takdra Lukhong, once again launched a joint invasion together with to participate in the rebellion of Pugu Huai'en against the Tang Dynasty, as well as the joint invasion of the Tang territory by the Khitans (later renamed as the Khitans), Tuyuhun, Dangxiang, Nulah, and other tribes.

Among them, the Tubo forces headed from the northern route towards Fengtian county, followed by the Khitan forces. The Dangxiang troops (referring to the Dangxiang tribe that had originally surrendered to the Tang Dynasty) departed from the eastern route to Tongzhou (in Dali County, Shaan'xi province). The Tuyuhun and Nulacha tribes moved towards Zhuxi from the western route. The military arrangements indicated an alliance and coordinated advance between these various forces.

The Tang Dynasty dispatched troops to guard strategic locations, making it difficult for the combined operations of Tubo and other invaders. The instigator of this offensive, Pugu Huai'en, fell ill midway and returned, later dying. Subsequently, the Tubo army, consisting of 100,000 soldiers, arrived at Fengtian county via Binzhou, once again shaking Chang'an. The Shuofang military commander Hujian, who defended Fengtian county, displayed great bravery and skill, engaging in battles with the Tubo forces many times. According to historical records, the Tubo forces suffered a casualty count of more than 15,000.

The armies of the Tang Dynasty and the Tubo Kingdom engaged in a protracted battle near the city of Chang'an. The people inside the city were in a state of panic, and even eunuchs suggested that the Tang emperor seek refuge in Hezhong. At this moment, heavy rain poured down from the sky, making it difficult for the Tubo army to launch an attack in the rain. They had to change their route and attack Liquan (north of Lixian County, Shaanxi province), where they engaged in widespread burning, killing, and looting. They captured tens of thousands of male and female Tang Dynasty civilians before retreating. Meanwhile, the Dangxiang tribe raided Bai Shui (Bai Shui County, Shaanxi) from the west and invaded Pu Jin (east of Dali County, Shaanxi) from the east.

In winter, the Tubo army retreated with their spoils to Binzhou, where they encountered the advancing Khitan forces. The Tubo and Khitan forces then turned eastward together. The Tubo and Khitan coalition besieged Jingyang (Jingyang, Shaanxi), but Tang General Guo Ziyi ordered his troops to hold their ground and not engage in battle. Around this time, news of Pugu Huai'en's sudden death spread. The Tubo and Khitan forces, in their dispute over the leadership position, set up separate camps, with the Khitans settling in the west of the city.

Taking advantage of the situation, General Guo Ziyi, a pillar of the Tang Dynasty, rode with a few soldiers to the camp of the Khitan to persuade them. Guo Ziyi had previously established a good relationship with the Khitan and was highly respected and trusted by them. Guo Ziyi was able to dispel the Khitan's hostility towards the Tang Dynasty. With his strategic thinking and foresight, Guo Ziyi's lecture changed the entire battlefield situation. The pressure on the Tang capital, Chang'an, was instantly relieved. The alliance between Tubo and the Khitan disappeared, and they became mutually opposed due to Guo Ziyi's successful manipulation.

Facing a treacherous battlefield created by the ever-changing night, the Tubo forces retreated overnight. The newly formed alliance between the Khitan and the Tang Dynasty pursued them closely. They defeated the Tubo troops in the west of Lingtai, Jingzhou, and other places, recapturing over 4,000 people who had been plundered by Tubo army. According to the "Old Book of Tang • Biography of Guo Ziyi," it is said that the Khitan and Tang Dynasty forces annihilated over 50,000 Tubo soldiers and captured 10,000.

In 766 AD, in the 2^nd month of the lunar calendar, Tubo Dynasty sent envoys to the Tang Dynasty. In the same month, Emperor Daizong of Tang dispatched Yang Ji, the Deputy Minister of the Ministry of Justice, to visit Tubo and "renew friendly relations" with Tubo Dynasty

In the 9^th month of the lunar calendar, a Tubo delegation consisting of more than a hundred people, led by their Chief Prime Minister Lun Trizang (also known as Lun Trizang Yabla), accompanied by Yang Ji, whom was back to the Tang Dynasty, to further establish good relations.

In the 9^th month of the lunar calendar, according to the "Book of New Tang • Annals of Emperor Daizong," Tubo army captured Yuanzhou. Additionally, according to the "Imperial Geography of the Yuanhe Era," Tubo army also captured Ganzhou and Suzhou. Yang Xiuming, the military governor of Hexi, relocated the capital to Shazhou (Dunhuang, Gansu).

Tubo engaged in both negotiations and military attacks simultaneously. They made significant progress in the Hexi corridor region, and most of the area came under Tubo's rule.

In the same year, construction of the Samye Monastery was completed after four years.

In 767 AD, in the 2^nd month of the lunar calendar, the Tang Dynasty sent an envoy named Xue Jingxian to visit Tubo to "reestablish old relations."

In the 4^th month of the lunar calendar, Emperor Tang Daizong of Tang ordered the prime minister, Yu Chaoen, to meet with Tubo envoys at the Xingtang Temple. This was known as the “Dali Alliance Meeting".

In the 7^th month of the lunar calendar, Tubo once again sent envoys to Tang Dynasty for an alliance. At that time, Tubo had a strong military force, and almost every alliance was accompanied by the outbreak of war.

In the 9^th month of the lunar calendar, tens of thousands of Tubo soldiers besieged Lingzhou (southwest of Lingwu County, Ningxia). At the same time, Tubo cavalry roamed around Panyuan (east of Pingliang County, Gansu) and Yilu (Changwu County, Shaanxi), causing the capital of the Tang Dynasty, Chang'an (present-day Xi'an, Shaanxi Province), to declare martial law.

In the 10^th month of the lunar calendar, Tang Dynasty's Shuofang Jiedushi, Lu Sigong, defeated Tubo near the city of Lingzhou, causing the Tubo army to retreat. As Tubo army failed to gain any advantage, the Tubo dynasty sent envoys to Tang Dynasty asking for an alliance meeting in order to discuss the division of borders

In the 11^th month of the lunar calendar, the Tang Dynasty envoy Xue Jingxian returned from Tubo dynasty. The Tubo minister, Lun Qiling, came to Tang dynasty and proposed that the boundary be set at Fenglin Pass. Fenglin Pass is located in present-day Linxia County, Gansu. This indicates that although Tubo army roamed in areas such as Longyou and Shuofang, however, they did not establish solid control over many counties in Longyou.

In the same year, Trisong Detsen erected a monument to commemorate the achievements of Nganlam Takdra Lukhong in attacking the Tang Dynasty. The Enlan Dazhalugong Monument is the earliest surviving Tubo stone inscription.

In the same year, Tubo army launched an attack on the kingdoms in the region of India known as Tianzhu. Many small kingdoms on the northern banks of the Ganges surrendered and became vassals of Tubo Dynasty. The Tubo army crossed the Ganges and attacked the Magadha kingdom in central Tianzhu, reclaiming the relics of Buddha. Magadha became a vassal state of Tubo dynasty. The Tubo army stationed four soldiers along the banks of the Ganges, established the Ganges as the border, and erected a large iron pillar to mark the boundary between Tubo dynasty and Tianzhu kingdom.

In the same year, Tubo king, Trisong Detsen, sent envoys again to invite "Zhi bavitso" and Master Padmasambhava from India to Tibet, bringing with them the lineage and teachings of Nalanda Monastery and Esoteric Buddhism. In this year, Tubo began extensive translation of Buddhist scriptures within its territory.

In 768 AD, Chimshang Gyalsig Shuteng, a prominent general in charge of the eastern region of Tubo (according to document P.T.1287, he also held the position of Tubo's prime minister), was highly respected and requested to retire.

Chimshang Gyalsig Shuteng was replaced by Zhang Tsanba as the military governor of the eastern region of Tubo dynasty, specifically responsible for managing the regions of Hexi corridoe and Longyou. The newly appointed Zhang Tsanba continued Tubo's consistent style of launching proactive attacks.

In the 8^th month of the lunar calendar, a hundred thousand Tubo troops attacked Lingwu (southwest of Lingwu County, Ningxia). Then, Zhang Tsanba personally led twenty thousand cavalry straight towards Binxian, penetrating deep into the rear of the Tang army, intending to harass the Tang forces and facilitate the attack on Lingwu. Binxian was close to Chang'an, the capital of the Tang Dynasty, which was under martial law. However, Zhang Tsanba failed to capture Binxian and eventually withdrew his troops. At the same time, the Tubo forces attacking Lingwu also made no progress.

In the 9^th month of the lunar calendar, in order to defend against Tubo army and protect Chang'an, the Tang general Guo Ziyi stationed fifty thousand troops in Fengtian. In that month, the Tubo forces reorganized their attack on Lingwu. Li Baoyu, the military governor of Fengxiang, sent Li Sheng with one thousand soldiers to pass through the Dazheng Pass and launch a surprise attack on Tubo's Dingqin Fortress in Lintao ("The Tubo Kingdom's ambition was to annex the regions of Qin,long, so they built fortresses in Taozhou and named it 'Dingqin'"). They burned down the Tubo's accumulated grain and captured the fortress commander Murong Guzhong. Upon hearing this, the Tubo forces besieging Lingwu retreated. Due to Tubo's continuous threats to Chang'an, the Tang Dynasty adjusted its military deployment and placed a heavy emphasis on defending the Chang'an area.

In 769 AD, in the 9^th month of the lunar calendar, Tubo's army entered the territory of Lingwu and plundered.

In the 10^th month of the lunar calendar, Tubo troops entered Mingsha County (southwest of Qingtongxia City, Ningxia). The Tubo army was numerous and stretched for over forty li (approximately 20 kilometers). Fearing the loss of Lingzhou, Tang general Guo Ziyi sent Hun Jian with five thousand elite soldiers to support. Soon after, the Tubo troops retreated.

In 770 AD, Tubo army attacked and plundered Yongshou County (northwest of Yongshou County, Shaanxi). This may seem like a small-scale harassment, but the ease with which Tubo's troops entered the northwest direction of the Tang's capital Chang'an indicates that the Tang Dynasty was in a passive defensive position in its northwest region.

In 771 AD, in the 4th month of the lunar calendar, Tubo Dynasty and the Tang Dynasty sent envoys to reconcile.

In the 9^th month of the lunar calendar, Tubo troops crossed Qing Shi Ridge (west of Yuanzhou, southwest of Linjing) and stationed at the Nacheng of Yuanzhou (southeast of Guyuan, Ningxia). Due to persuasion from Tang general Guo Ziyi, Tubo troops later withdrew.

In the same year, the debate between Buddhism and Bön ended in the failure of Bön. Tubo's king, Trisong Detsen, used this as a reason to ban Bön within Tubo's territory and vigorously promote Buddhism.

In 772 AD, the reorganized Tubo army launched another seasonal raid.

In the 8^th month of the lunar calendar, sixty thousand Tubo cavalry attacked and plundered Lingwu, trampling crops before leaving.

In the 10^th month of the lunar calendar, Tubo invaded Jingzhou and Binxian. Hun Jian, the commander of the Tang's Shuofang military governor's forces, led his troops and fought against Tubo army in Yilu (Changwu County, Shaanxi), where he strategically placed anti-cavalry spikes to prevent Tubo cavalry charges. However, some of his subordinates did not follow his orders and left, resulting in a disastrous defeat for the Tang army. Deputy general Shi Ji and three other generals of Tang dynasty were killed in battle, and the majority of the soldiers were lost, and Tubo army captured thousands of local villagers.

Afterward, General Ma Lin of the Tang Dynasty fought a major battle against the Tubo army at the salt warehouse to the west of Jingzhou City, and Tubo emerged victorious. Later, General Hun Jian and Ma Lin launched another attack and recaptured some of the spoils from Tubo army, causing the Tubo army to retreat.

In 773 AD, in the 8^th month of the lunar calendar, over sixty thousand Tubo cavalry raided Lingwu, trampling the autumn crops and then leaving.

In the 10^th month of the lunar calendar, Tubo army, with a force of one hundred thousand, raided Jingzhou, Binxian, and other prefectures.

In 774 AD, Wu Sun, a Tang Dynasty official traveled to Tubo dynasty as envoy, was detained by Tubo dynasty. He died of illness in Tubo's capital Lhasa in the 2^nd month of the lunar calendar. Afterwards, the Tubo Kingdom launched several years of Autumn Harvest Wars against the Tang Dynasty.

According to Guo Ziyi's memorial to the Tang Emperor, he mentioned that Tubo had recently penetrated deep into the interior and established four military commands, each with over ten thousand troops. Based on this, the military command of the East region of Tubo dynasty should have around one hundred thousand troops.

Note: that during the period of Trisong Detsen, "military commands" were established along the Tang-Tubo border, such as the Lacheng Military Command and Songzhou Military Command, all located on the front lines of Sichuan and Yunnan. Here, "military command" has two meanings: one refers to the military office, and the other refers to the highest official in the military office, also known as a military commissioner in historical Chinese texts.

In 775 AD, in the 9^th month of the lunar calendar, Tubo army attacked Linjing (Zhenyuan, Gansu) and entered Longzhou (Long County, Shaanxi), plundering people and livestock before leaving. They then attacked Jingzhou and were repelled by Ma Lin, the military commissioner of Jingyuan, at Baili City (Baili Town, southwest of Lingtai County, Gansu).

Note: that Trisong Detsen laid the foundation for the construction of the Samye Monastery. According to the record of "Yubo Gan Ge," construction of the Samye Monastery began in the year 775 AD and was completed in 779 AD. There is a conflict in the construction timeline with the previous mention of the Samye Monastery. Another account states that when Trisong Detsen was 34 years old, in the Year of the Wooden Rabbit (775 AD), the Samye Monastery was fully constructed, taking a total of thirteen years to complete.

In 776 AD, the Tubo Dynasty launched a large-scale military campaign in the present-day region of Sichuan and Yunnan, mobilizing an army of 200,000 troops led by four regional commanders. The army consisted of various tribes, including the Turks, Tuyuhun, Min, Man, Qiang, and Dangxiang. However, due to its overly complex structure, Tubo's subordinates were unwilling to engage in a prolonged battle. They were ultimately defeated by the Tang general Cui Ning, who commanded the army of the West Sichuan regional military command. Tubo suffered heavy losses, with over ten thousand casualties, as well as the loss of cattle, sheep, and military equipment, which fell into the hands of the Tang army.

In the 9^th month of the lunar calendar, Tubo launched an attack on Shimen in its eastern front line, capturing Chang-ze-chuan (north of Yanzhou, Wuyuan, Xiazhou, which is now Gu Yuan County in Ningxia). They also occupied Guazhou.

In 777 AD, Tubo dynasty again launched an attack on its southern front, besieging Lizhou (north of Hanyuan County, Sichuan) and Yazhou (Ya'an County, Sichuan) in the 4^th month of the lunar calendar but failed to achieve any success.

In the 10^th month of the lunar calendar, the Tang general Cui Ning led his army to defeat Tubo at Wanghancheng, a fortress built by Tubo in the western mountains.

In Tubo's eastern front line, in the 9^th month of the lunar calendar, an army of 80,000 Tubo soldiers invaded Yuanshou, the northern part of Chang-ze-chuan, broke through Fangqu County (Huan County, Gansu), and entered Bogu (belonging to Qingzhou). The Tang general Guo Ziyi sent Li Huaiguang to aid, and the Tubo army fled southeast, attacking and plundering Fangzhou (Huangling, Shaanxi) before leaving.

In the 10^th month of the lunar calendar, Tubo attacked Yanzhou (Dingbian County, Shaanxi), Xiazhou (Baichengzi in northeast of Jingbian County, Shaanxi), and Changwu (Yulin, Binzhou).

In 778 AD, in the 2^nd month of the lunar calendar, Tubo's prime minister Nganlam Takdra Lukhong (known as Ma Chongying in Chinese historical records) led 40,000 soldiers to attack Lingzhou, capturing the outlets of the three canals: Tianhan, Yushi, and Shangshu, in order to disrupt the Tang Dynasty's agricultural settlements.

In the 4^th month of the lunar calendar, Tubo attacked Lingzhou again.

In the 7^th month of the lunar calendar, Tubo army of 20,000 troops to attack and plunder Yanzhou and Qingzhou.

In the 8^th month of the lunar calendar, Tubo's 20,000 troops attacked the area around Yinzhou and Lin (north of Shenmu County, Shaanxi), plundering and driving away the livestock of the Dangxiang tribe.

In the 9^th month of the lunar calendar, 10,000 Tubo cavalry crossed the Qingshiling Mountains (northwest of Jingchuan County, Gansu) and advanced towards Jingzhou.

Tubo cavalry frequently operated in the interior of Tang Dynasty's territory for several years, indicating that the Tang Dynasty maintained control over strategic military strongholds while the vast plains were left to the Tubo army to roam freely. Although Tubo launched frequent military attacks, the Tang Dynasty's armies tightly defended their cities, keeping the Tubo army in a state of guerrilla warfare with no substantial progress.

In 779 AD, the first complete Buddhist temple in Tubo Dynasty, the Samye Monastery, was completed (some sources say it was completed in 766 AD). At the Samye Monastery, the "Alliance Stele for the Prosperity of Buddhism" was erected, with the inscription stating that the Tubo king and his subjects pledged to honor and follow Buddhism for generations, making it the state religion.

In the same year, Emperor Dezong of Tang dynasty ascended the throne following the death of Emperor Tang Daizong.

In the 8^th month of the lunar calendar, the Tang Dynasty sent Wei Lun, the Sima of Suizhou,to Tubo dynasty as envoy, while to return the previously detained Tubo envoys and 500 prisoners of war along with gifts. Tubo welcomed the return of the envoys and prisoners, and sending people to greet Wei Lun.

In the same year, the king of the Nanzhao Kingdom, Geluofeng, passed away, and his grandson Yimouxun succeeded him as the king of Nanzhao kingdom.

In the 10^th month of the lunar calendar, Tubo and Nanzhao launched a joint campaign with the aim of making progress in the Sichuan and Yunnan regions. They mobilized a total of 100,000 troops and attacked the Tang Dynasty from three directions: one towards Maozhou, one towards Fuzhou (Nanping, Sichuan) and Wenzhou (southwest of Wen County, Gansu), and one towards Li and Ya, passing through Qionglai Pass.

At the beginning of this offensive, the Tubo-Nanzhao coalition captured several prefectures and counties, causing the local Tang officials and armies to abandon the cities and flee, with soldiers hiding in the valleys. Later, the Tang general Li Cheng led elite troops into Shu (Sichuan) to stop the Tubo-Nanzhao offensive and launched a counterattack. Li Cheng's forces achieved a great victory, inflicting heavy losses on the Nanzhao-Tubo coalition. The coalition forces were driven into the valleys, where around 80,000 to 90,000 soldiers died due to hunger and cold, as well as falling off cliffs. This victory greatly shocked Yimouxun, who relocated the capital to Yangjumei City (Dali, Yunnan). To appease Yimouxun, Tubo sent envoys to confer him the title of "King of Rizhong".

Since Nanzhao kingdom became a vassal state of Tubo, Tubo collected taxes from Nanzhao and often ordered Nanzhao's army to participate in battles. In order to further control Nanzhao kingdom, Tubo established military camps in strategic locations, which placed a heavy burden on Nanzhao. Yimouxun, who had been influenced by Chinese culture since childhood, combined with Tubo's several unsuccessful wars, gradually became dissatisfied with Tubo dynasty. Cracks began to appear between Tubo dynasty and Nanzhao kingdom, and Yimouxun started to lean towards the Tang Dynasty.

Note: Both the Tang Dynasty and Tubo Dynasty sent envoys to each other, and sometimes these envoys were detained as hostages. During the reign of Emperor Tang Daizong, the Tang Dynasty detained eight batches of Tubo envoys.

In 780 AD, Tubo Dynasty and Nanzhao kingdom formed a coalition and attacked Chengdu (now Chengdu, Sihcuan province). However, they were defeated by the Tang army. Tubo blamed Nanzhao for the failure and reduced its status to a vassal state. This decision led to Nanzhao ultimately aligning itself with the Tang dynasty.

In the 4^th month of the lunar calendar, Tubo dynasty sent envoys with Wei Lun to return to Tang dynasty and discuss peace with Tang dynasty

In the same year, General Liu Wenxi occupied Jingzhou and defected to Tubo. He sent his son as a hostage to Tubo dynasty and requested military assistance. However, at this time, the relationship between Tang dynasty and Tubo dynasty had slightly improved, and Tubo dynasty did not support Liu Wenxi's rebellion.

In the 5^th month of the lunar calendar, Tang Dezong dispatched Wei Lun as an envoy to Tubo dynasty and released the Tubo soldiers who had been captured during the attack on Jiannan. Wei Lun received great hospitality in Tubo dynasty, and historical records state: "When Tubo king and officials first saw Wei Lun, they were happy to welcome him. Upon arriving at the residence, there were music and dance performances to entertain him, and he stayed for nine days before returning.

In the 12^th month of the lunar calendar, Wei Lun returned to Tang to report, accompanied by 55 Tubo officials, including the Tubo prime minister Lunqin Mingsi. Their main task was to negotiate the alliance between Tang dynasty and Tubo dynasty

In 781 AD, Tubo Dynasty conquered Hami and Shazhou (present-day Dunhuang, Gansu). The Tubo king, Trisong Detsen, issued an edict inviting the Indian monk Mahayana to Tubo for missionary work. In that year, Mahayana set off for Tubo (there are also claims that it was in 786 AD, or 787 AD, or 788 AD).

In the 3^rd month of the lunar calendar, the Tang Dynasty sent an envoy, Cui Hanheng, to Tubo with the main task of negotiating an alliance between Tang Dynasty and Tubo Dynasty.

In the 12^th month of the lunar calendar, when the Tang envoy Cui Hanheng entered the Tubo territory, the Tubo dynasty stopped him midway, demanding to see the Tang imperial edict held by Cui Hanheng before arranging an audience with the Tubo king. After reviewing the Tang imperial edict, Tubo dynasty protested against the traditional way that Tang referred to Tubo as a subject, as Trisong Detsen believed that the relationship between Tang and Tubo was that of an equal nephew and uncle, not a hierarchical one. Therefore, Tubo sent an envoy to convey the king's opinion and requested that the border between Tubo and Tang be established west of Lingzhou, with Helan Mountain as the boundary. The Tang Dynasty agreed to modify the imperial edict according to Tubo's request and accepted Tubo's demand for border demarcation.

In that same year, after more than a decade without any communication, envoys from Beiting Jiedushi (Military Governorship) Li Yuanzhong and the Four Garrisons led by Guo Xin arrived in Chang'an for the first time. The envoys came through the Uighurs, indicating that Beiting and the Anxi Four Garrisons were still under the control of the Tang Dynasty. However, this did not mean that Tubo did not have military actions in the Western Regions. Prior to this, Tubo advanced through the Hexi Corridor and besieged Yizhou (now Hami in Xinjiang). After adopting the strategy used in the capture of Yanzhou, they tried to persuade the governor of Yizhou, Yuan Guangting, to surrender the city. However, Yuan Guangting strongly resisted and mobilized all forces to defend the city. Several years later, the city ran out of food, with no additional support and the Tubo forces captured it. Yuan Guangting killed his wife and then committed self-immolation. The Tang dynasty only received this news in 781 AD and posthumously honored Yuan Guangting as the Minister of Works, while promoting Guo Xin, who was guarding Anxi Four Garrisons alone, to the position of Grand Protector of Anxi and Observer of the Four Garrisons.

Note: The timing of Tubo's conquest of Shazhou (Dunhuang, Gansu) has different versions.

Note: The timing of Mahayana's journey to Tubo also has different versions, including in the year 786 AD or 787 AD, 788 AD.

Note: Tubo's Buddhism was influenced by Chinese Mahayana Buddhism since the time of Songtsen Gampo. In the latter half of the 8^th century, Tang Dynasty monks took turns to go to Tubo to preach and teach. According to the "Cefu Yuangu" (Volume 980, Section of Foreign Relations), in the second year of the Jianzhong era (781 AD), Tubo sent an envoy to seek a good Buddhist speaker, and the monks Liangwang Xiu and Wensu were sent, with each of them serving for two years. "Tang Huiyao" states that "the two monks served on a rotating basis every year." Many monks and nuns from the Tang Dynasty also arrived in Tubo as prisoners of war during the Tang-Tubo wars. In summary, many Tang Dynasty monks were engaged in missionary work, translation, and other activities in Tubo.

In 782 AD, in the 4^th month of the lunar calendar, Tubo dynasty returned approximately 800 captured Tang Dynasty soldiers, generals, monks, nuns, as well as the coffins of the deceased generals Yang Xiuming, Zhou Ding, Li Qizhang,and Zhang Tie, as a gesture of gratitude to the Tang Dynasty.

In the 9^th month of the lunar calendar, Cui Hanheng returned from Tubo, accompanied by the Tubo minister Ku Dratsan.

In the 10^th month of the lunar calendar, the Tang envoy Fan Ze was appointed to go to Tubo dynasty to finalize the alliance between the two sides. Fan Ze and Zhang Gyatsan made preparations for the alliance in Qing Shui. At this time, there were frequent exchanges of envoys between Tang dynasty and Tubo dynasty, and the two sides were preparing for a larger meeting.

As the frontlines of the war extended, Tubo was eager for the Tang Dynasty to recognize the territories it had already occupied. At that time, the Tubo minister Chimshang Gyalsig Shuteng opposed reconciliation with the Tang Dynasty due to the defeat in Jiannan (now, Sichuan province). The vice Tubo minister Zhang Gyatsan advised the king, requesting a meeting to establish boundaries for the benefit of the border people affected by the war. Trisong Detsen agreed with Zhang Gyatsan's suggestion and replaced Chimshang Gyalsig Shuteng with Zhang Gyatsan as the Tubo minister (according to the "Genealogical Table of Ministers" from Dunhuang Tubo documents, after Chimshang Gyalsig Shuteng, the minister was Nganlam Takdra Lukhong, and then Zhang Gyatsan).

In 783 AD, on the 10^th day of the 1^st lunar month, the chief prime minister of Tubo dynasty, Zhang Gyatsan, and the Tang Dynasty general Zhang Yi, who was stationed in Longyou, held a meeting at Qing Shui (northwest of Qingshui County, Gansu). This was a solemn oath-taking ceremony between ministers or border commanders of the Tang Dynasty and Tubo Dynasty at the border.

The initial agreement for the "sacrificial items" used by the meeting of allies was that the Tang Dynasty would provide cows, and the Tubo Dynasty would provide horses.

However, during the alliance meeting, according to the "Old Book of Tang, Tubo Biography," Zhang Yi said to Zhang Gyatsan, "The Han people cannot cultivate without cows, and theTubo people cannot travel without horses. Now, I propose to replace them with sheep, pigs, and dogs." Zhang Gyatsan agreed to Zhang Yi's request, however, he pointed out that the Tubo did not have pigs (although they actually did have pigs, with even more pigs in the Tubo-occupied areas, but the Tubo people rarely used pigs for religious sacrifices). Instead, he proposed using rams, which were sacrificial offerings for the Tubo people, as a substitute.

The meeting ceremony was held in a grand manner, with officials from both sides swearing an oath in blood and reading the alliance text written in their respective languages.

From the treaty, it can be seen that Tubo's territory greatly expanded, extending to the border between Shaanxi and Gansu in the eastern region, and the Tang Dynasty acknowledged this fact. However, the delineation of the border between the two sides was somewhat ambiguous and rough in some places, and there were complications during this meeting.

After the meeting at Qing Shui, the Emperor of the Tang Dynasty ordered the prime minister and the minister of state to once again hold a meeting with the Tubo dynasty's Ku Dratsan and oteher ministers. However, the Tubo minister, Ku Dratsan, raised objections, believing that the "Qing Shui meeting" did not clearly define the borders, and further discussions were needed. Therefore, Tang dynasty sent Cui Hanheng to negotiate with Tubo officials.

In the 6^th month of the lunar calendar, the Tang envoy Yu Di and the Tubo envoy traveled from Qinghai to Chang'an, suggesting that the border issue had already been settled, indicating that the decision of the "Qing Shui meeting" was still upheld.

In the 7^th month of the lunar calendar, the important officials of the Tang Dynasty held an alliance meeting with Tubo ministers, including Ku Dratsan, in the west of Chang'an City, with the same ceremonial customs as the Qing Shui meeting.

On the 9^th day of the 7^th month of the lunar calendar, after the meeting in Chang'an. The Tang Dynasty appointed the Minister of Rites, Li Kui, as the envoy for the meeting and sent him to Tubo dynasty for the alliance. He went to Tubo dynaty along with the Tubo minister Ku Dratsan. In fact, there were three meetings held during this time, one within the territory of Tang dynasty and Tubo dynasty, and one in the border area. Tubo Dynasty and the Tang Dynasty signed the "Qing shui Alliance," ending the hostile state

In the same year, the Tang Dynasty experienced the "Rebellion of Zhu Ci." The Tubo dynasty requested to send troops to assist the Tang Dynasty in suppressing the rebellion.

In the same year, on the western front of Tubo dynasty, the Abbasid Caliphate, led by Harun al-Rashid, whom succeeded as the Khalifah, sought to prevent Tubo from further expansion and engaged in competition with Tubo dynasty in Central Asia. According to the "Old Book of Tang, Abbasid Caliphate Biography," it is mentioned: "After the death of Musa, his brother Harun al-Rashid succeeded him as the Khalifhh (786-809). During the Zhenyuan period (785 AD - 805 AD), they became sworn enemies with Tubo dynasty. As the majority of the Tubo army was deployed in the west against the Abbasid Caliphate, they posed little threat to the borders with Tang dynasty, indicating their insufficient strength."

In 784 AD, the "Qing-Shui Alliance" improved relations between the Tang Dynasty and Tubo Dynasty.

In the 1^st month of the lunar calendar, Tubo dynasty's prime minister Zhang Gyatsan expressed willingness to send troops to help the Tang Dynasty suppress the rebellion led by Zhu Ci and recapture the capital. The Tang Dynasty sent official Cui Hanheng to negotiate with Tubo regarding this matter.

In the 2^nd month of the lunar calendar, Cui Hanheng arrived in Tubo's territory, and Zhang Gyatsan said, "According to Tubo's military regulations, the signature of the chief minister must be present for the deployment of troops. As the official letter does not have the signature of Li Huaiguang, I dare not proceed." Therefore, Emperor Dezong of the Tang Dynasty asked Li Huaiguang to sign a document requesting Tubo to send troops. However, Li Huaiguang believed that Tubo's military assistance to the Tang Dynasty would cause three harms, and then stubbornly refused.

In the 4^th month of the lunar calendar, Cui Hanheng persuaded Zhang Gyatsan again and promised to give territories such as Yixi and Beiting to Tubo after the success of the mission. As a result, Zhang Gyatsan sent General Lunmang loyi with 20,000 soldiers to assist General Hun Jian of Tang Dynasty in battle against Han Sheng, who was attacking Wugong. Initially, Hun Jian's forces were not successful and retreated to the west. However, they encountered 3,000 soldiers under General Cao Zida of Tang dynasty and Tubo troops, and in a subsequent battle against Han Sheng at Wutingchuan, the rebels were defeated with over 10,000 casualties. After the victory, the Tubo soldiers looted the area but did not advance further against the rebel forces. This was because Zhu Ci had sent his subordinate Tian Xijian to offer gold and silk as bribes to Tubo army. The Tubo troops gained significant benefits and, coupled with the outbreak of diseases among the soldiers in the spring, Zhang Gyatsan withdrew his troops.

In the 6^th month of the lunar calendar, Zhu Ci hurriedly fled west towards Tubo dynasty in search of a lifeline but was shot by one of his own officers along the way, marking the end of the rebellion.

In the 7^th month of the lunar calendar, Tubo sent envoy to Tang dynasty demanding territories such as Beiting. Emperor Dezong prepared to recall the military governors of the two regions and fulfill their promises, but faced opposition from his ministers whom believed that Tubo had been passive in suppressing the rebellion and that territories such as Yixi and Beiting were strategically important and should not be easily handed over to Tubo dynasty. As a result, the emperor changed his stance, and Tubo's wishes were not fulfilled. Zhang Gyatsan felt deceived and began plotting the war of Qiu-yue. The "Qing-Shui Alliance" was thus abandoned.

In the same year, in Lhasa, "Zhi batso" assumed the position of the first teacher at Samye Monastery. He passed away this year due to a fall from a startled horse. He was succeeded by his disciple Baye shewangpo, also known as Ba sanang before ordination.

In 785 AD, it was a relatively quiet year, Tubo army did not engage in any military activities in its eastern region.

On its southern front, Tubo army launched small-scale border raids against the southwest garrison of the Tang Dynasty. Wei Gao, the military governor of Jiannan Xichuan, sent envoys to establish friendly relations with Nanzhao kingdom, and subsequently defeated Tubo's invading forces.

In 786 AD, in the 2^nd month of the lunar calendar, the Tang Dynasty sent Li Yu, the Imperial Censor, as an envoy to Tubo Dynasty.

In the 8^th month of the lunar calendar, Zhang Gyatsan, the prime mnister of Tubo dynasty led a large army to invade states of Tang dynasty such as Jingzhou (Now, the north of Jingchuan county, Gansu province), Longzhou (Now, Long County, administrated by Baoji City, Shaanxi province), Binzhou (Now, Bingzhou City, Shaanxi province), and Ningzhou (Now, Ning County, Gansu province). They plundered people and livestock, harvested crops, and departed with their spoils. Faced with the rampant Tubo cavalry, the various states and counties of the Tang Dynasty could only close their doors and defend themselves.

On the 19^th day of the 9^th month of the lunar calendar, Tubo's cavalry reached Haozhi (Yiyang Old city, in the southwest of Yongshou County, and northwest of Gan County, Shaanxi province). Chang'an, the capital of Tang Dynasty, was once again placed under martial law. Each time Tubo sent troops, they approached Chang'an, posing a great threat to the Tang Dynasty, and there were even rumors among the people that the emperor of Tang dynasty was planning to flee Chang'an, which causing unrest among the people

On the 25^th day of the 9^th month of the lunar calendar, Tubo's army attacked Fengxiang county (Now,Fengxiang District, administrated by Baoji City, Shaanxi province). The Tang Dynasty dispatched troops to defense, meanwhile sent General Kang Cheng as an envoy to Tubo army. Kang Cheng met with Zhang Gyatsan at Shangze Yuan. During the meeting, Zhang Gyatsan consistently claimed that the border between Tubo dynasty and Tang dyasty was unclear, which was one of his excuses for launching the war. He also sent Lun Chito to accompany Kang Cheng as an envoy to the Tang Dynasty to negociate. Since the 8^th month of the lunar calendar, when Tubo sent troops, they did not completely withdraw, and their cavalry roamed in the aforementioned areas.

In the 9^th month of the lunar calendar, when Zhang Gyatsan's army passed by Qianyang City in Longzhou (Long County, Shaanxi), they were attacked by Wang Bi, a general under Li Sheng. They were defeated, and Shang Jiezhan narrowly escaped capture. It was said that the Tang soldiers did not recognize Shang Jiezhan, which is why he was spared.

In the 9^th month of the lunar calendar, when Zhang Gyatsan, the leader of the Tubo army, passed through Qianyang City in Longzhou （Now,Long County, Shaanxi province), Tubo army was attacked by Tang army led by Wang Bi, a general under Li Sheng. The Tubo army was defeated and fled. Zhang Gyatsan narrowly escaped being captured and was saved only because the soldiers of the Tang Dynasty did not recognize him as the enemy leader.

In the 10^th month of the lunar calendar, Tang dynasty's General Li Sheng sent Yeshi Liangfu and Wang Bi to lead ten thousand infantry and cavalry to attack Tubo's Cui-Sha Fort (Now, northwest of Guyuan County, Gansu). They burned Tubo's grain and forage reserves, and Tubo's defenders, including Hu Guqu Lu Simeng, were killed in the battle. The army led by Zhang Gyatsan camped north of Heshui County (Now, Heshui County, Gansu Province). Han Youjing, the military governor of Binning, sent General Shi Lucheng to launch a surprise attack on the Tubo camp at night, killing and injuring hundreds of Tubo soldiers. The Tubo army pursued them, but Han's troops laid an ambush in Pingchuan and secretly sent soldiers entering the western mountain to beat drums, causing the Tubo army to retreat in panic

In the 11^th month of the lunar calendar, Tubo's army besieged Yanzhou (Dingbian County, Shaanxi province - north of Yanchi County, Ningxia province). They surrounded the city layer by layer and pass the message to the governor of Yanzhou, Du Yanguang, "We want to occupy the city, you can lead your people to leave." Du Yanguang followed Tubo's instructions and led his troops to abandon the city. Tubo's army entered Yanzhou without a fight and took control of the city.

In the 12^th month of the lunar calendar, Tubo's army attacked Xiazhou (Baichengzi town, in the northeast of Jingbian County, Shaanxi - now located in Shaanxi and Inner Mongolia). They used the same strategy and ordered the governor to leave the city. They easily captured Xiazhou, and then attacked Yinzhou (Dongdangcha Town, Hengshan County; in the northwest of Mizhi county, Shaanxi province). At that time, "the officials and people of Yinzhou all fled," Tubo army then attacked Linzhou (north of Shenmu County, Shaanxi). Zhang Gyatsan dispatched over a thousand people to defend each of the captured towns and cities, and he personally led the main force to camp at Mingsha. This area in the northern part of Shaanxi province became Tubo's sphere of influence.

In the meantime, Zhang Gyatsan's strategy of sowing discord began to take effect. Li Sheng's political rival, Zhang Yanshang, took advantage of this and slandered Li Sheng in his report to the emperor of Tang dynasty. The Tang emperor was also wary of Li Sheng's achievements, so Li Sheng had no choice but to resign and express his willingness to become a monk. However, Li Sheng was an esteemed and outstanding general, and the emperor couldn't afford to lose him. Emperor Tang Dezong had no choice but to reconcile Zhang Yanshang and Li Sheng.

Within four months, Tubo launched almost continuous attacks on the border towns of the Tang Dynasty. The western border of the Tang Dynasty was engulfed in flames of war.

Note: One important objective of Tubo's war was still to plunder wealth and food, rather than solely focusing on attacking individual counties or states. The Autumn-war brought wealth for the ruling class of Tubo dynasty to enjoy and indulge in luxury, while also providing provisions for Tubo soldiers and putting immense pressure on the Tang Dynasty's defense in the northwest. However, the local residents became the victims of the war. Tubo's savage plundering war caused significant losses to the livelihoods and production of the local civilians.

In 787 AD, in the 2^nd month of the lunar calendar, Tang Dynasty sent the imperial censor and left magistrate Cui Wan (Li Xian?) as an envoy to Tubo.

This was due to the natural disasters that occurred in Tubo dynasty from the previous winter to the spring of this year. Many sheep and horses died, making it difficult to transport military rations. The three famous Tang generals, Li Sheng, Ma Sui, and Hun Jen, led their troops, and being vigilant on the border. Therefore, Tubo's prime minister Zhang Gyatsan abandoned military attacks and instead to use diplomatic tactics. He sent envoys to negotiate with the Tang Dynasty multiple times and set up a series of stratagems. Zhang Gyatsan stationed over a thousand troops in Yanzhou (Dingbian County, Shaanxi province - north of Yanchi County, Ningxia province) and Xiazhou (Baichengzi town, in the northeast of Jingbian County, Shaanxi - now located in Shaanxi and Inner Mongolia), while he himself retreated to Mingsha (east of Zhongwei County, Gansu province). Then after, Tubo dynasty requested peace talks with the Tang Dynasty, which were accepted.

On the 15^th day of the 5^th lunar month, Hun Jen and Zhang Gyatsan met in Pingliang (northwest of Pingliang County, province). On that day, Tubo's Zhang Gyatsan launched a surprise attack in Pingliang, capturing more than sixty civil and military officials of the Tang Dynasty, as well as over a thousand soldiers. This event was known as the "Tubo Hijacks "Alliance Meeting" in Pingliang." After that, Zhang Gyatsan led his troops to destroy Yanzhou and Xiazhou before retreating.

In the 8^th month of the lunar calendar, Tubo prime minister Zhang Gyatsan released the captured Cui Hanheng and submitted another request for peace talk to the Tang Dynasty. However, the Tang general Li Guan, who was in charge of border defense, refused Tubo's envoy, stating, "There is an imperial decree that not to accept Tubo's envoys." Tubo's attempt at peace was unsuccessful, so they initiated a war. Tubo army divided into three forces and attacked Longzhou (Now, Long County, administrated by Baoji City, Shaanxi province), Qianyang (northwest of Qianyang County, Shaanxi province), and Diaogan Yuan. The Tubo army established camps for dozens of miles, and their camp in Qianyang was forty li away from Fengxiang (Now,Fengxiang District, administrated by Baoji City, Shaanxi province). The capital of Tang dynasty was in shock and the people were terrified. Zhang Gyatsan sent his forces disguised in Tang soldiers' uniforms, pretending to be Xingjun Ya's troops. They suddenly entered Wushan (northwest of Baoji County, Shaanxi) and its northern area, launching a frenzy of plundering against the local residents. The Tubo army burned down houses, drove away livestock and the people, and severed the head of the Wu Mountain god, which was worshipped locally (located in the sputhwest of Long county, Shaanxi province). According to historical records such as the "Book of Tang," the Tubo army was extremely cruel, killing or mutilating the elderly, weak, sick, and disabled by cutting off their hands and gouging out their eyes. They then expelled the strong and able-bodied individuals, sending them to labor in areas where there was a shortage of manpower, such as Hexi corridor and other regions. Tang General Li Sheng had ordered his troops to block the Anhua Gorge (in the jurisdiction of Zhangjiachuan Hui Autonomous County, Gansu province) with felled trees to hinder Tubo's army, but Zhang Gyatsan destroyed Li Sheng's plan with fire.

In the 8^th month of the lunar calendar, Emperor Dezong of Tang issued an edict admitting his mistakes and cutting off diplomatic relations with Tubo dynasty. The Tang-Tubo relationship was thus severed, and from the 8^th month of 787 AD to the 4^th month of 803 AD, there was no communication between Tang dynasty and Tubo dynasty for 16 years. The Tang prime minister, Li Bi, proposed a strategy of "forming alliances with the Khitan in the north, establishing communication with Yunnan in the south, and forming a relationship with Abbasid Caliphate and Tianzhu kingdom in the west." The goal was to unite the surrounding powers of Tubo dynasty and implement a strategy of encirclement, causing Tubo to become trapped. Emperor Dezong of Tang dynasty accepted this proposal.

In the 9^th month of the lunar calendar, Tubo army launched a major attack on the Tang Dynasty, plundering the people in Qianyang, Wushan, Huating (Huating County, Gansu province), and other areas. More than tens of thousands of people were driven to the west of Anhua Gorge, to be distributed to Qiang, Hun, and other tribes. Tubo army allowed them to face east and bid farewell to their homeland. Among them, more than a thousand people chose to commit suicide by jumping into deep valleys.

Shortly after, the Tubo army launched another attack, besieging Longzhou. The governor of Longzhou, Han Qinghe, and the deputy general of the Shence Army, Su Taiping, launched a surprise attack at night, causing the Tubo army to retreat. The Tubo army then surrounded Huating, cutting off the water source and trapping General Wang Xianhe and three thousand soldiers and common people in a dilemma of being surrounded by the Tubo army and lacking water. Wang Xianhe sought help from Longzhou, and Han Qingmian ordered Su Taiping to lead fifteen hundred soldiers to Huating. On the way, they were ambushed by the Tubo army. Over a hundred riders were captured by the Tubo army, and Su Taiping ordered a retreat.

The Tubo army sent more than a thousand cavalry to harass the surroundings of Longzhou daily, and the Longzhou soldiers dared not leave the city. After four days of preparation, the Tubo army piled up materials near Huating city, preparing to set the city on fire. Wang Xianhe found in a desperate situation and had no choice but to surrender to Tubo army

After that, the Tubo army launched another attack on Lianyun Fortress (northwest of Jingchuan County, Gansu province), which was a strategically important location. Lianyun Fortress was similar to Shibao Fortress, with steep cliffs on three sides and only a connection to the plains on the north side. The Tang army dug trenches and defended the fortress. The Tubo army used various methods to attack the fortress, building seven catapults to throw stones from high ground, filling the only well in the fortress with stones. They then launched a fierce assault from the north over the trenches. General Zhang Mingyi surrendered with his troops.

Lianyun Fortress was located west of Jingzhou and was used by the Tang army to monitor the movements of the Tubo army. After its capture, Tang army dared not open the west gate of Jingzhou, and the area outside the gate became a place where Tubo troops freely roamed. When the farmers of Tang Dynasty harvested crops, Tang army had to send troops to protect the harvest. However, often due to Tubo's invasions, the harvest season was lost, resulting in a crisis in local food supply. The Tubo cavalry plundered and drove away tens of thousands of residents and livestock from Binzhou and Jingzhou to the Danzhen Gorge. The Tang garrison's response was minimal, only sending messengers to congratulate the emperor when the Tubo army returned with rich spoils, declaring that the "bandits" had retreated.

In the 10^th month of the lunar calendar, the Tubo army launched another attack on Fengyi City (southeast of Zhenyuan County, province) and Changwu City (northwest of Changwu County, province) . Tubo's cavalry roamed between Jingzhou and Binzhou, and the local towns of the Tang Dynasty did not dare to open their west gates. Tubo army repaired the old city of Yuanzhou as a place for the army to reside. However, due to the cold climate, Tubo's food supply was not sufficient, so they soon ceased military actions.

In the same year, on the western region of the northern front of Tubo Empire, the Tang Dynasty's Governing Prefectures of Anxi consisted of four towns: Kucha, Shule, Yutian, and Yanqi. Due to continuous infiltration by Tubo forces, it was challenging for the Tang Dynasty to maintain complete control over these four towns. In the "Book of New Tang · Gazetteer" (Volume 40), it states: "In the third year of Zhenyuan (787 AD), Tubo army attacked the Shato, Huihe and Beiting, and without reinforcements, they subsequently are captured by Tubo army

787 AD: Tubo Hijacks "Alliance Meeting" in Pingliang

In 787 AD, in the 4^th month of the lunar calendar, Cui Wan once again went to negotiate with Tubo's prime minister Zhang Gyatsan about the alliance. Tang Dynasty maintained a cautious attitude towards Tubo dynasty. Cui Wan informed Zhang Gyatsan that Tang officials Du Xiquan and Li Guan could not attend the alliance, and only sent Hun Jian to attend the alliance. Cui Wan also proposed that Tubo dynasty should return the two states of Yanzhou and Xiazhou before the alliance. Shang Jiezan did not give a clear response to this.

In the 5^th month of the lunar calendar, the Tang Dynasty sent Hun Jian as the envoy for the Alliance, with Cui Han Heng, the Minister of War, as the deputy envoy, Zheng Shujun, a junior official, as the judge, and palace eunuch Song Fengchao as the commander of the military. Zhang Gyatsan sent Lunqizan, a subordinate, to express to Tang dynasty's officials that "Qingshui" was an ominous place and requested the alliance to take place at Tu Li Shu in Yuanzhou, and after the alliance, return Yanzhou and Xiazhou. Emperor Dezong of Tang eagerly agreed. However, General Ma Youlin thought that Tu Li Shu was treacherous and suspected that Tubo might set an ambush there, so he suggested changing the location of the alliance to Pingliangchuan (Now, near Pingliang county, Gansu province). Based on Tang's opinion, the two sides decided to hold the alliance in Pingliangchuan.

In the 5^th month of the lunar calendar, Zhang Gyatsan and Hun Jian met in Pingliang. They agreed that each side would send three thousand soldiers to stand on the east and west sides of the alliance altar, with four hundred attendants in regular attire at the foot of the altar. During the alliance, Zhang Gyatsan proposed that dozens of scouts from each side should monitor each other. Zhang Gyatsan had prepared in advance for the alliance, ambushing tens of thousands of cavalry on the west side of the alliance altar. Tubo's cavalry freely moved in and out of the ranks of the Tang army. When Hun Jian's subordinate, Lianfeng, arrived with sixty riders near the Tubo army, they were captured by the Tubo troops without Hun Jian's knowledge. Zhang Gyatsan let Hun Jian and others enter the tent to change into the ceremonial dress for the alliance. Just as the Tang officials were changing their clothes inside the tent, the Tubo army beat the drum three times, and the elite Tubo cavalry, who had been waiting for a long time, suddenly shouted and launched an attack on the Tang officials and soldiers.

Tubo's main target was Hun Jian, who lived up to his reputation as a brave general. He escaped from the tent and mounted a war horse, riding away. The Tang generals and soldiers all rushed to the east to escape, but Tubo army pursued them closely. Over a thousand people were captured, and several hundred were killed. Hun Jian fled to his own camp, but it had already been emptied. He then rushed into Luo Yuanguang's camp, and only then did Tubo give up the pursuit. Among the Tang officials attending the alliance, Song Fengchao was killed by the Tubo soldiers, and most of them became prisoners of Tubo. There were about sixty officials and generals in total. This was the "Tubo Hijacks "Alliance Meeting" in Pingliang", a trap carefully designed by Zhang Gyatsan

However, Zhang Gyatsan did not expect Hun Jian to escape. When he saw Cui Han Heng, he said that he had originally prepared a pair of golden shackles to capture Hun Jian and present them to the emperor of Tubo. But Zhang Gyatsan quickly changed his mind and came up with another plan. In front of everyone, he said to Ma Yan, the nephew of Ma Sui, "The Hu (referring to Tubo) values horses as their lives. When I was in Hequ, the spring grass had not yet grown, and the horses could not move. At that time, the Prime Minister (referring to Ma Sui) would cross the river and ambush them, and our entire army would be destroyed! That's why I sought peace, thanks to the Prime Minister's help. Now that the whole army has returned, why should we detain their offspring?" After praising Ma Yan, he released him along with the eunuch Ju Wenzhen and Hun Jian's subordinate, Ma Ning.

Zhang Gyatsan's move was well-calculated because Ju Wenzhen would surely repeat Zhang Gyatsan's words in front of the emperor of Tang dynasty, and Ma Ning would definitely inform Hun Jian. This can be seen as a strategy to sow discord among the Tang courtiers. As expected, when Emperor Tang Dezong heard the news, he was displeased and removed Ma Sui from his position as Vice Marshal and Military Governor, and transferred him to the capital as Minister of Education and Prime Minister. Ma Sui also lost his military power. Cuihan Heng, Zheng Bujv, and others were sent to prison in Hezhou and other places. With this move, Zhang Gyatsan achieved his goal of causing suspicion and discord among the Tang courtiers. His two formidable enemies left the battlefield one after another. Shangjiezan's calculations were indeed well-executed.

The Tubo soldiers guarding Yanzhou and Xiazhou suffered from a lack of military supplies, many fell ill, and they longed for their hometowns. In addition, the two states were devastated by war and became desolate. Zhang Gyatsan sent three thousand cavalry to welcome them, and the Tubo army burned down houses and drove away the people before they returned to the Tibetan plateau

In 788 AD, the Tang Dynasty implemented a "Guanzhong-centric" policy, with the focus of the country in the northwest. However, Tubo dynasty occupied most of Longyou (The region between Longshan and the Yellow River includes Tianshui City, Pingliang City, Dingxi City, and Lanzhou City）and directly threatened Chang'an, making it difficult for the Tang Dynasty to defend against them. Therefore, in the year 787 AD, the Chancellor of the Tang Dynasty, Li Mi, proposed the strategy of "making peace with the Khitans in the north, establishing communication with Nanzhao Kingdom in the south, and forming an alliance with the Abbasid Caliphate and the Kingdom of India in the west". The aim was to unite the surrounding powers of Tubo dynasty and implement a strategy of encirclement to weaken Tubo dynasty.

Tang Dynasty placed emphasis on strengthening relations with the Khitans and Nanzhao kingdom. Tang Dynasty also focused on the southwestern front to alleviate pressure on its north. Wei Gao, the Tang general, became the implementer of this strategy and achieved great success. On the other hand, Tubo army mobilized its entire troops for multiple offensives, which weakened their defensive capabilities and dispersed their forces, making it difficult for them to achieve much. Wei Gao continuously courted the hesitant Nanzhao kingdom.

In implementing this new strategy, Tang Dynasty first rebuilt Lianyun Fort to defend against Tubo's attacks. The Tang Dynasty also married a princess to the Khitan Khan Heguolu, and the Khitan Khan Hegudulu Pijia was pleased with the marriage proposal. He sent his sister, Princess Hegudulu Pijia, along with over a thousand people including ministers and officials, to welcome the Tang princess in Chang'an. The Khitan Khan expressed his loyalty to the Tang Dynasty, saying, "In the past, we were brothers, and now we are in-laws. If Tubo Dynasty becomes a threat, I will help you eliminate it." In the 9^th month of lunar calendar, the Khitans insulted Tubo's envoy and severed relations with Tubo.

On the western front of Tubo, the Tang Dynasty's garrisons troops in Anxi and Beiting (Due north of Jimsar County, Xinjiang) returned to the Tang Dynasty through the assistance of the Khitan. Although the Tang Dynasty controlled some important military strongholds in the Western Regions, they were already weak and vulnerable. The Shatuo tribes with over six thousand tents, the Geluolu tribes, and the Bai Fu Turks in the Beiting region were all attached to the Khitans, and the Beiting region was already within the sphere of influence of the Khitans. However, Tubo dynasty had favorable conditions to capture Beiting, as the rule of the Khitans had caused resentment among the local tribes, and the Khitan army often oppressed and plundered these tribes. Tubo's spies persuaded and instigated this tribes to rebel against the Khitans, offering certain benefits to their leaders. Therefore, even before the outbreak of war, Tubo dynasty had already found alliance forces in local.

In the 4^th month of lunar calendar, the king of the Nanzhao Kingdom, Yimouxun, began to make contact with the Tang Dynasty. He first sent emissaries like "Guizhu Biaopang," "Ju Mengchong," and "Ju Wuxing" to establish indirect relations with the Tang Dynasty.

In the 5^th month of lunar calendar, Tubo army changed its tradition of attacking in autumn and winter and retreating in spring. Instead, they launched a war of plunder in the peak summer season. With over 30,000 cavalry, Tubo raided states such as Jingzhou (Now, the north of Jingchuan county, Gansu province), Binzhou (Now, Bingzhou City, Shaanxi province), Ningzhou (Now, Ning County, Gansu province), Qingzhou (Now, Qingyang City, Gansu Province and southern Ningxia), and Fuzhou (Fu County, Shaanxi Province), plundering over 20,000 people and livestock of the Tang Dynasty in just over twenty days. Due to Tubo's large military deployments in the Western Regions, Sichuan, and Yunnan, they held the advantage in the Longyou region but lacked troops. Therefore, in this year, Tubo had some captured Tang soldiers joining their ranks.

In the 9^th month of lunar calendar, Tubo generals like Shangxi Dongxing and Lun Mangluo led troops to attack Ningzhou. Tang military governor Zhang Xianfu led his forces to counterattack,causing Tubo's army to change direction and ravage states like Linzhou and Fangzhou. In the eastern region, during the autumn season, Tubo almost annually launched wars using highly flexible cavalry guerrilla tactics. They swiftly entered strategic destinations, conducted major plunder, and quickly retreated.

In the 10^th month of lunar calendar, Tubo dispatched a 100,000-strong army to attack the Western Sichuan region, while they also had tens of thousands of Nanzhao troops stationed north of Lushui. At that time, Wei Gao, who was in charge of the southwest for the Tang Dynasty, was very strategic. He desperately wanted Nanzhao kingdom to break away from Tubo's influence. Wei Gao wrote a letter to the King of Nanzhao, recounting Nanzhao's rebellion against Tubo and their return to the Tang Dynasty, placing the letter deliberately in a silver box to be delivered to Tubo via the Dongman. When Tubo's commanders received the letter, they fell into Wei Gao's scheme, suspecting Nanzhao kingdom. They dispatched 20,000 troops to block the route between Nanzhao kingdom and Sichuan at Huichuan (now, west of Huili County, Sichuan Province). in order to prevent Nanzhao troops entering Sichuan

Tubo's actions displeased Nanzhao kingdom, and the king - Yimouxun, who led his troops, returned to his kingdom. From then on, suspicion grew between Tubo and Nanzhao. While Tubo's influence weakened, but they did not retreat. They split their forces, with 40,000 attacking the "Lianglin" and "Biaopang" tribes, 30,000 attacking "Dongman tribe," 7,000 attacking "Qingxi Pass" (now, southwest of Hanyuan County, Sichuan Province), and 5,000 attacking "Tongshan" (northwest of Hanyuan County, Sichuan Province). Tubo's forces were scattered, and they suffered defeat outside Qingxi Pass. In the end, the Tang Dynasty completely defeated Tubo's offensive in Xichang (now, Xichang city, Sichuan province).

In the 11^th month of lunar calendar, Tubo once again sent over 20,000 troops to attack Qingxi Pass and 10,000 to attack Dongman tribe. However, the outcome was the same as the previous attack. In the same year, Tubo sent envoys multiple times to the Nanzhao Kingdom in an attempt to strengthen their relationship.

In 789 AD, in the 9^th month of lunar calendar, Tubo army launched an attack on Longzhou (now Long County, Shaanxi Province), Jingzhou (Now, the north of Jingchuan county, Gansu province), and Binzhou (Now, Bingzhou City, Shaanxi province).

In the l0^th month of lunar calendar, Wei Gao, the Tang military governor of Xichuan, sought the support of Nanzhao kingdom while launching an offensive against Tubo dynasty. He dispatched General Wang Youdao and a coalition army consisting of the Dongman tribe and Lianglinman tribe to face the Tubo forces led by the commanders of Qinghai and Lacheng in the Taideng Valley of Gouzhou. In the battle, they killed Tubo's famous general, Qizang Zhezhe, dealing a significant blow to Tubo's army. However, Tubo still held control over Sichuan's Guizhou until several years later when it was finally recovered.

In the l2^th month of lunar calendar, in the Western Regions, Tubo's army allied with tribes such as Gelu and the Bai Fu Turks to launch an attack on Beiting (Due north of Jimsar County, Xinjiang). The Uighur leader Jieyusu rushed to aid the city but faced unfavorable circumstances.

In 790 AD, in the 5^th month of lunar calendar, Jiegang Jieyusu's Uighur army was defeated by Tubo army, and Tubo launched a fierce attack on Beiting (Due north of Jimsar County, Xinjiang). The Shatuo tribal chief Zhuxie Jinzhong, who had already established contact with Tubo, surrendered with his troops. The Beiting military governor Li Xigu, facing internal and external troubles, led 2,000 troops to flee to the Xizhou (southeast of Turpan, Xinjiang). Tubo finally captured Beiting, extending their influence north of the Tianshan Mountains.

In the autumn of that year, Jiegang Jieyusu mobilized the majority of the fighting force in the Uighur Kingdom, assembling an army of tens of thousands and joining forces with Li Xigu to prepare to reclaim Beiting. This sparked another battle between Beiting and Tubo, resulting in another defeat for Tubo. Tubo annihilated a large portion of the Uighur forces, and the Battle of Beiting concluded with Tubo's glorious victory.

While the Uighurs suffered defeat twice at Beiting, Tubo also incurred losses with a significant number of casualties among their troops. From then on, the connection between the Tang Dynasty and the Western Regions was severed. Taking advantage of their victory, Gelolu captured the Uighur's Futuchuan, and the Uighur tribes in the northwest were relocated to the south of the Tubo's camp.

The inscription at the end of Volume P.3981 of the Dunhuang documents, titled "The Vajra Mandala Sutra," was written by Zhao Yanbin, a former judge of the Tang administrative office in Yizhou (Xinjiang's Hami), Xizhou, and Tingzhou, who later became the resident of the Ganzhou. The inscription was made in the 9^th year of Zhenyuan (during the year 793 AD), stating that "the previous year (meaning the 8th year of Zhenyuan, 792 AD) Xizhou was lost," indicating that Tubo occupied Xizhou in 792 AD.

In the same year, a dispute known as the "sudden enlightenment"-"gradual enlightenment" Controversy erupted in Tubo's capital Lhasa and lasted for two years (the exact timing of the controversy is disputed, ranging from 790 to 792 AD).

Note: Beiting (now, Beiting Township, Jimsar County, Xinjiang)

1. In the year of Tubo's capture of Beiting, it was in the sixth year of Tang Zhenyuan (790 AD). "Zizhi Tongjian" believes that after Tubo captured Beiting, "Anxi was cut off, and no one knew its survival or demise." As mentioned earlier, Tubo's influence entered the Pamir region early, and it is possible that Tubo captured Anxi around the third year of Zhenyuan (787 AD). The historical Tibetan documents in Dunhuang also have records of Tubo's capture of Yutian. "During this time of the Zanpu (Trisong Detsan), Meilu Chisuren Muxia launched an attack on Duohan (Upper land), and Yutian became a subordinate state, subject to taxation and tribute." Volume P.T.1089 also mentions that Tubo bestowed the title of king upon Yutian and granted them silver and imperial edicts. Tubo Dynasty also established a military office in Yutian, and many Tibetan wooden slips and documents have been unearthed in places like Mazhatage in Yutian, reflecting Tubo's effective rule in this region.

Due to the "Anshi Rebellion," the Tang Dynasty's power in the Western Regions rapidly weakened, with areas west of the Pamir Mountains falling under the influence of the Abbasid Caliphate, while the Pamir Mountains and areas to the east belonged to Tubo dynasty. From the second half of the 8th century to the middle of the 9th century, from Hexi in the east to the Pamir region in the west, especially the areas south of the Tianshan Mountains, were under Tubo's rule or influence.

2. Furthermore, the Tang Dynasty had promised Tubo Dynasty that if they assisted in suppressing the Zhu Ci Rebellion (Jingyuan Mutiny), they would be willing to give Beiting and other territories to Tubo. Although Tubo did not fully commit to suppressing the Zhu Ci Rebellion, they did provide some assistance. Afterward, Tubo demanded the promised territories, but Tang ministers like Li Bi strongly opposed the emperor's recall of the military governors of the two towns. Tubo's plan to obtain Beiting and other territories could not be realized.

At this time, the Tang Dynasty implemented a strategic policy of allying with Nanzhao kingdom in the south, connecting with the Uighurs in the north, and forming an alliance with the Abbasid Caliphate to encircle Tubo dynasty. "The Abbasid Caliphate was the most powerful in the Western Regions, extending from the Pamir Mountains to the Western Sea, covering almost half of the world. Both India and the Western Regions admired China, while the Tang Dynasty and Tubo Dynasty were enemies."

The rise of the Uighurs from the northern desert penetrated from east to west in the posture of the overlords of the northern grasslands. It is clear that in order for Tubo to break the encirclement strategy of the Tang Dynasty, they had to confront the Uighurs and Arab forces infiltrating the Western Regions from both the east and the west. "Tang Huiyao" records: "In the 2^nd year of Zhenyuan (786 AD), the Abbasid Caliphate and Tubo became fierce enemies. Most of the Tubo troops were directed westward against the Abbasid Caliphate, so they rarely posed a threat." Tubo launched an expedition from their northwest homeland and fought against the Arabs in the so-called "Upper Region." Although there is a lack of detailed records, however, Tubo still established a foothold in the "Upper Region," Bruzha and some small countries in the Pamir areas submitted to Tubo. Tubo effectively deterred further eastward expansion of the Abbasid Caliphate, protecting the Western Regions (now, Xinjiang) from Arab's invasion.

In 791 AD, on the eastern front of Tubo dynasty, Tang's Jingyuan Military Governor Liu Changzhu led his troops and local people to build the Pingliang town and the Chaogu Fortress (west of Pingliang County, Gansu) to block Tubo's advance. On the southern front of Tubo dynasty, although the Kingdom of Nanzhao did not respond to Tang general Wei Gao's persuasion to surrender, however, the number of troops sent by Nanzhao to assist Tubo gradually decreased whenever Tubo launched an attack.

After the Weigao dispatched the former envoy to Nanzhao in the 6^th month of the lunar calendar, Duan Zhongyi, who served as the deputy envoy for military strikes, was sent to Nanzhao kingdom.

In the 6^th month of the lunar calendar, Wei Gao dispatched Duan Zhongyi, a former envoy of Nanzhao who remained in the Tang dynasty as a deputy general for military operations, to persuade Yimouxun - the King of Nanzhao kingdom to return to Tang's side. When Tubo dynasty learned about this, they sent envoys to question Yimouxun, who defended himself by saying, "Tang's envoy is originally a barbarian, and Wei Gao only wants me to return, nothing more." However, Tubo's distrust of Nanzhao grew stronger. They somehow managed to bring many sons of Nanzhao's ministers to Tubo as hostages. It was thought that this was a wise move by Tubo officials, but it backfired as Yimouxun grew even more resentful towards Tubo. Tubo dynasty also encouraged the tribal chief Wudeng Jumengchong to incite the other tribes cutting off the route for Nanzhao's envoys to reach the Tang dynasty. To counter Tubo's strategy, Wei Gao sent the commander Su Yu of the three tribes (Liulin, Wudeng, and Fengpa) to lead troops to Piba River. In the 2^nd year of 792 AD (Tang's Zhenyuan era, eighth year), they captured and killed Jumengchong, who was obedient to Tubo dynasty, thus opening up the Yunnan route. From then on, Tang's military could directly reach the border of Nanzhao kingdom.

In the 8^th month of the lunar calendar,on the eastern front, Tubo attacked Lingzhou (now, Lingwu City, Ningxia province) but was defeated by the Uighur army and retreated at night.

On the southern front, Tang general Wei Gao led his troops to attack Tubo's Weizhou castle (now,Zagunao Town, Li County, Sichuan) capturing the Tubo general Lun Tsanren (some sources say this happened in 792 AD), but they still failed to capture the city of Weizhou.

The mutual suspicion between Tubo dynasty and Nanzhao kingdom deepened. Whenever Nanzhao mobilized its troops, Tubo also sent troops, claiming it was for mutual support, but in reality, Tubo dynasty had already sensed that Nanzhao kingdom was unreliable. Wei Gao took the opportunity to send a letter to Nanzhao king, proposing a joint attack on Tubo to maintain Nanzhao's independent status.

In the 12^th month of the lunar calendar, the Uighurs offered the captured Tubo general Zhang Gyaltsen as a gift to the Tang Dynasty. At this time, the Uighurs had become a formidable enemy of Tubo dynasty.

In 792 AD, in the 4^th month of the lunar calendar, on the eastern front of the Tang Dynasty's border, Tubo launched another military attack on Lingzhou (now, Lingwu City, Ningxia province), and causing destruction to the farmland before retreating.

In the 6^th month of the lunar calendar, Tubo sent over a thousand cavalry into the territory of Jingzhou (Now, the north of Jingchuan county, Gansu province), capturing over a thousand Tang soldiers who were engaged in farming. When the Tubo troops reached Lianyun Fortress, the Tang garrison commander sent out troops to fight, but they were defeated by the Tubo army, and General Wang Jin Yong died in the battle.

In the Western Regions, Tubo army seized control of Gaochang and Hotan. However, the army of the Uighur Khanate subsequently expelled Tubo army from Gaochang, Kucha, and Yanqi.

In the same year, the three-year-long Buddhist dispute between the "sudden enlightenment" and "gradual enlightenment" factions came to an end.

Note 1: In the Tibetan historical book "Yubo Gangge," the "Sudden enlightenment" and "Gradual enlightenment" dispute lasted from 792 to 794 AD. The debate lasted for three years, from the year 792 AD to 794 AD. There were language barriers for both sides of the debate as they did not understand each other's languages. It is possible that Tibetan was used as the common language for the debate, and the papers of both sides were also translated into Tibetan.

Regarding the outcome, general Tibetan historical books state that the debate ended with the failure of the Chan (Zen) school of Chinese Buddhism. Mahayana presented a flower wreath to Lianhua Jie （Zhi batso's student）as a sign of surrender and then returned to Dunhuang. Many disciples of the Chan school were dissatisfied and some even practiced self-immolation or defied Lianhua Jie. However, Trisong Detsan declared that Tibetan Buddhism should be based on the Madhyamaka (Middle Way) school, prohibiting the spread of the Chan school. Mahayana's works were all concealed.

Note 2: Although Buddhism was introduced to Tubo dynasty during the reign of Songtsen Gampo, it did not become mainstream. It was during the reign of Trisong Detsan that the combined influence of Vajrayana Buddhism from India and Mahayana Buddhism from China merged with the indigenous Bön religion to form Tibetan Buddhism. After the Buddhist-Bön dispute, Buddhism was declared the victor by the king and gradually established as the state religion of Tubo dynasty. This religion propagated doctrines such as cosmic catastrophe, impermanence, karma, samsara (cycle of birth and death), and the path to liberation through practice. It particularly revered Vajrayana, with the highest practice being the highest yoga tantra, known as the Tibetan Esoteric Buddhism.

This was the first wave of Buddhism's introduction to Tibetan plateau, and religious historians refer to it as the "early propagation period" or "Snga dar" of Tibetan Buddhism. For more detailed information about the three-year-long Buddhist dispute between the "sudden enlightenment" and "gradual enlightenment", please refer to the "Records of Tubo Monastic Debates“.

In 793 AD, in the 2^nd month of the lunar calendar, the Tang Dynasty rebuilt Yan-zhou City (Dingbian County, Shaanxi province) on the site of Wuyuan. They stationed troops to defend against Tubo's encroachment on Lingzhou and Xiazhou, and the Tang army recaptured Yanzhou (now, Yan'an, Shaanxi).

At the same time, the Tang Dynasty's strategic campaign against Tubo army in the southwest region was going smoothly. In the 5th month of the lunar calendar, General Wei Gao led troops to the western mountains, capturing more than fifty strongholds established by Tubo army. The military victory of Wei Gao had a significant impact, leading Nanzhao King Yi Moushun to firmly decide to break away from Tubo dynasty. He sent envoys along three routes to Chengdu, proclaiming himself as the grandson of the Prince of Yunnan of Tang Dynasty. He expressed his determination to abandon Tubo dynasty and join Tang dynasty, presenting a silk document as evidence.

Tubo dynasty supported many smaller tribal chieftains who were loyal to Tubo dynasty along its southern front line. They also established vassal kings among the tribes surrounding the Nanzhao Kingdom. Tubo aimed to divide the power of Nanzhao kingdom, which was something Nanzhao kingdom was wary of. Nanzhao's concern was that Tubo would use other tribes to replace its position. Nanzhao's submission to the Tang Dynasty had its own difficulties and hesitations.

Nanzhao's defection and Wei Gao's continuous advances put Tubo dynasty in a disadvantageous position in the regions of Sichuan and Yunnan. The Eight Qiang Kingdoms, which were previously wavering between Tubo and the Tang Dynasty, began to lean towards the Tang Dynasty.

During the two years from this year to 795 AD, Tubo ceased launching wars in its eastern frontier and border areas with the Tang Dynasty.

In 794 AD, the "Sudden enlightenment" and "Gradual enlightenment" dispute between the Indian Madhyamaka school and the Chinese Chan (Zen) school came to an end, and Tibetan Buddhism subsequently adopted the "Gradual enlightenment" as its mainstream. The representative of the Chinese Chan school, Mahayana, was sent back to Dunhuang

In the 1^st month of the lunar calendar, Cui Zuoshi, an envoy sent by Wei Gu, the military governor of Jiannan Jiedushi, arrived in the capital of Nanzhao kingdom, Yangzhumei. At that time, Tibetan envoys were also active in Nanzhao kingdom. Nanzhao King Yi Moushun had concerns, but after being persuaded by the Tang envoy Cui Zuoshi and others, Yi Moushun publicly broke off ties with Tubo dynasty, revoked the titles granted by Tubo king, held a meeting with Cui Zuoshi, and decided to jointly deal with Tubo dynasty while maintaining non-aggression between Tang dynasty and Nanzhao kingdom.

Tubo envoys were also captured and killed by Nanzhao kingdom, but the news of the rupture between Nanzhao kingdom and Tubo dynasty had not reached Tubo at that time. Tubo dynasty was engaged in a major war in the Western Regions and was short of soldiers, so they conscripted 10,000 soldiers from Nanzhao kingdom. However, Yi Moushun declined due to the small size of his country and ultimately decided to send 5,000 soldiers. On the day of the expedition, Nanzhao King Yi Moushun let the 5,000 soldiers march ahead while secretly following with his main army. They marched day and night and launched a surprise attack on Tubo army in the Shenchuan area, cutting off Tubo's key transportation bridge to Nanzhao kingdom and capturing sixteen Tubo castles east of Iron bridge (northwest of Zhongdian County) and more than 100,000 Tubo soldiers including five Tubo vassal kings.

Yi Moushun's defection greatly weakened Tubo's power in Yunnan, which was good news for the Tang Dynasty and further solidified the Tang Dynasty's defense line against Tubo army in Sichuan.

In the 6^th month of the lunar calendar, Nanzhao King Yi Moushun sent his brother Cou luolian to present maps, local offerings, and the golden seal bestowed by Tubo king to the Tang Dynasty which immediately sent Yuan Zi, a senior official from the Ministry of Rites, as an ambassador to confer the silver seal of the Tang Dynasty to Yi Moushun,inscribed with the words "Zhenyuan Seal of Nanzhao kingdom".

From this point on, the once close allies Tubo dynasty and Nanzhao kingdom turned into adversaries, while the competition between Tubo Dynasty and the Tang Dynasty in the southwest region weakened both sides, leaving a tremendous opportunity for Nanzhao kingdom to dominate the southwest.

In 795 AD, Nanzhao kingdom seized control of Kunming City(now Yanyuan County, Sichuan province), which was previously held by Tubo dynasty.

In 796 AD, Tubo army launched an attack on Qingzhou (now Qingyang, Gansu province), but the war came to a sudden halt with the death of the renowned Tubo commander Zhang Gyatsan, who was a courageous and strategic leader, serving as the highest military and political commander in the eastern part of the Tubo dynasty. He also held the position of Tubo's great prime minister, making decisions on a series of policies towards the Tang Dynasty. With Zhang Gyatsan's death, the wars in the eastern region of Tubo dynasty under the reign of Trisong Detsan gradually quieted down.

In the same year, Trisong Detsan devoted himself to Buddhism, and in his later years, his devotion to Buddhism deepened. In order to focus on his spiritual practice, he decided to abdicate the throne to his 2^nd son, Mune, who succeeded him.

In 797 AD, in the 1^st month of the lunar calendar, Tubo dynasty sent envoys to the Tang Dynasty to submit a memorial, seeking reconciliation. Emperor Dezong of Tang dynasty, considering their treacherous nature, repeated breaches of trust, and refusal to accept previous memorials, dismissed their envoys.

In the same year, Emperor Dezong of Tang dynasty ordered the military commander Yang Chaocheng of Binning to construct three cities: Fangqu, Hedo, and Mubo, as well as fortifications along Malin Pass, in order to prevent the Tubo troops coming through the valleys along the Malin River.

On the northern front of Tubo, the Uyghur army defeated the Tubo garrison in Liangzhou（now, Wuwei city, Gansu province）.

On the southern front of Tubo, Tubo forces launched an attack in the present-day Sichuan-Yunnan region, advancing towards Taideng City (south of Mianning County, Sichuan). CaoGaoshi, the governor of Guizhou, led his troops to join forces with the local tribes to resist the Tubo attack, resulting in Tubo's failure.

Trisong Detsan was assassinated in the year 797. The Tubo royal family erected a monument called "Qiongjie Bridge Stele" at the tomb site in Qiongjie Village, which described Trisong Detsan's rule and achievements.

After Trisong Detsan's death, he left 4 sons. The eldest son, Mutri Songpo, died early, so the throne was inherited by the second son, Mune. At that time, Mune was only 23 years old. In the "New Book of Tang" and "Zizhi Tongjian," he is referred to as "Zu Zhi-Jian."

During the reign of Trisong Detsan, social contradictions in Tubo became increasingly acute, primarily due to the polarization between the rich and the poor.On one hand, the feudal landlord class and the nobility accumulated vast wealth through warfare and plunder, owning a large number of lands, pastures, and serfs. Additionally, the rewards bestowed by successive rulers further concentrated wealth in the hands of a small group of people. On the other hand, some commoners suffered from frequent wars and heavy taxation. Some fled, while others became increasingly impoverished, and even fell into slavery.

Note 1: There is confusion in historical records regarding the genealogy of the rulers between Trisong Detsan and Tride Songtsen. Some scholars believe that Trisong Detsan's rule ended in 794 AD. The "Old Book of Tang" states, "In the early part of the third month of the 20^th year of Zhenyuan of Tang dynasty, the Tsanpo passed away," referring to the year 804 AD when a certain Tibetan king died.

Note 2: There are also different accounts regarding the duration of Mune Tsanpo's reign. According to "The Nangshi Texts" (published by the Tibet People's Publishing House) on page 414, Mune Tsanpo ruled for 12 months and passed away at the age of 27. "The Red History" (Tibetan version) on page 38 states that Mune Tsanpo ruled for one year and nine months, passing away at the age of 24. " The Record of Tibetan Royal Ministers" (translated version on page 64) mentions that Mune Tsanpo ruled for one year and seven months. The "Old Book of Tang·Tubo Annals" states, "The Tsanpo passed away in the fourth month of the 13^th year of Zhenyuan of Tang dynasty, and his eldest son succeeded him, but died at the age of one, so the second son inherited the throne." Here, "died at the age of one" refers to Mune Tsanpo. In summary, Mune Tsanpo's reign lasted a little over a year.

Note 3: it is estimated that Tride Songtsen ascended the throne around 798 AD after the death of Mune Tsanpo. However, In another document granted to Myung Ting Ngejin, Mune Tsanpo's name is not mentioned, speculating that Mune Tsanpo died after Tride Songtsen ascended the throne.

In 798 AD, Mune Tsanpo was poisoned to death by his mother, and his reign lasted only one year and nine months. His political career became a victim of palace intrigue. Tride Songtsan was enthroned as the Tsanpo (Tibetan king). During this period, the Tubo dynasty was facing unprecedented internal and external crises.

Tride Songtsan further advanced the Buddhist movement in Tubo dynasty. Additionally, he made an innovation by ensuring that the chief prime minister and other ministers would follow the royal decree without secretly going against it due to religious differences, meanwhile, on the other hand, it was to facilitate the bureaucratic system in promoting the movement of Buddhist beliefs. He appointed Buddhist monks as prime ministers, known as "Monk Prime Minister" with the official title of "Ban de bkav la gtogs pa", He elevated the position of the Buddhist monk to be above that of the chief prime minister, making them the highest-ranking official in the bureaucratic system. With this, Tride Songtsan elevated the Tubo Buddhist movement to a new level.

In the 10^{th month of the lunar calendar, Han Quanyi, the military governor of Xiazhou in the Tang Dynasty, defeated the Tubo army in the northwest of Yanzhou (now, Dingbian County, Shaanxi province).}

In 798 AD, Mune Tsanpo was poisoned to death by his mother, and his reign lasted only one year and nine months. His political career became a victim of palace intrigue. Tride Songtsan was enthroned as the Tsanpo (Tibetan king). During this period, the Tubo dynasty was facing unprecedented internal and external crises.

Tride Songtsan further advanced the Buddhist movement in Tubo dynasty. Additionally, he made an innovation by ensuring that the chief prime minister and other ministers would follow the royal decree without secretly going against it due to religious differences, meanwhile, on the other hand, it was to facilitate the bureaucratic system in promoting the movement of Buddhist beliefs. He appointed Buddhist monks as prime ministers, known as "Monk Prime Minister" with the official title of "Ban de bkav la gtogs pa", He elevated the position of the Buddhist monk to be above that of the chief prime minister, making them the highest-ranking official in the bureaucratic system. With this, Tride Songtsan elevated the Tubo Buddhist movement to a new level.

In the 10^th month of the lunar calendar, Han Quanyi, the military governor of Xiazhou in the Tang Dynasty, defeated the Tubo army in the northwest of Yanzhou (now, Dingbian County, Shaanxi province).

In 799 AD, in the 12^th month of the lunar calendar, a 50,000-strong Tubo army attacked the Nanzhao kingdom and Lizhou. However, due to the tight defense by King Yimou Xun of Nanzhao and Wei Gu, the military governor of the southwestern region appointed by the Tang Dynasty, the Tubo army returned without any achievements.

Since Nanzhao had defected to the Tang Dynasty, Tubo Dynasty was in a passive position, fighting on both fronts in this region. The Tang Dynasty relied on military victories in the southwest to relieve pressure in its northwest.

While Tubo army was trying to leverage its strategic advantage in the Longyou and Hexi regions, it also attempted to reverse the unfavorable situation in Yunnan. Therefore, they gathered a large army and launched an offensive. This was a risky move for the understaffed Tubo forces.

In 800 AD, Tubo dynasty prepared to launch an attack in Yunnan and Sichuan again, with the goal of besieging Xizhou (now Xichang city, Sichuan Province). An 80,000-strong army stationed in Kunming with one year's rations, led by Rangdul, the uncle of Tride Songtsan, and stationed Zhang Krizu Ramshag and the army led by him in Xigongchuan.

Nanzhao kingdom and Wei Gao of the Tang Dynasty adopted a joint defense strategy. Tang general Kang Lechao stationed 10,000 troops in Lizhou (north of Hanyuan County, Sichuan province), while Wei Liangjin stationed 25,000 troops in Xizhou (now Xichang city, Sichuan Province), and they requested military support from Nanzhao kingdom. The Tubo army then divided into two routes from Nangongchuan, one attacking Yunnan and the other attacking Xizhou. However, before the Tubo offensive could unfold, Yang Wanbo, the defender of Yongcheng, intended to surrender to the Tang Dynasty. Tubo army discovered this and sent 5,000 troops to suppress the rebellion and guard Yongcheng, but they were defeated by Wei Gao's army. Yang Wanbo led 2,000 men to surrender to the Tang Dynasty.

Tang general Fu Zhongyi also captured Tubo's Mogongcheng, capturing thousands of cattle and sheep. Commanders of Tubo army continued to surrender one after another, including Nangong, Lacheng, and other military governors, as well as Ma Dingde, who was renowned for his intelligence and strategy. Most of the Tubo army followed his plans, but due to several unsuccessful expeditions, Ma Dingde and others feared punishment from the Tibetan king and decided to surrender to the Tang Dynasty.

Mune Tsanpo's adopted son, Yeduoshu Jian, the military supervisor of Xigong, also defected to the Tang Dynasty out of fear of being sacrificed for Mune Tsanpo's funeral. Many Tubo army's generals had lost their fighting spirit, morale was low, and the army was unstable. Only Zhang Krizu Ramshag led his troops to the Iron Bridge which was the advancing position, but due to Nanzhao's poisoning of the river, he retreated to Nacuan. That year, the frost and snow came early, and the Tubo army returned without any achievements.

In 801 AD, during the spring season, the Tubo army stationed around the Sanlu River was attacked by the forces of Nanzhao kingdom and the Tang Dynasty. The Tang army used a strategy of breaking the dams and flooding the Tubo soldiers. The Tubo army retreated to the Luwei Mountains but fell into an ambush set by the Tang army and suffered a major defeat. Soldiers from countries such as Abbasid Caliphate who fought alongside the Tubo army were captured by the Tang Dynasty army.

At that time, Tubo dynasty was greatly troubled by attacks from both Nanzhao kingdom and the Tang Dynasty, and they referred to Nanzhao as the "double-headed barbarians". According to the "New Book of Tang, Annals of Nanzhao", the ruler and officials of Tubo dynasty believed that the Nanzhao kingdom posed a significant threat to Tubo dynasty. They implemented a system called "Da Liaojie," which required every three households to provide one soldier to reinforce the army of Tubo dynasty. The garrison troops were ordered to strictly guard the cities of Nacuan, Guhong, Nuoji, Lacheng, and Yulai, in order to cut off communication between Nanzhao kingdom and Tang Dynasty at the appropriate time by taking control of Xizhou（now, Xichang city, Sichuan province）. Following these developments, Tubo army launched a series of attacks in present-day Ningxia and the northern part of Shaanxi province.

In the 7^th month of the lunar calendar, Tubo army advanced towards Yanzhou and later captured Linzhou (north of Shenmu County, Shaanxi), where they killed the commander Guo Feng (a grandson of Guo Ziyi). The Tubo army completely destroyed the city and looted the tribes of the Tanguts and local residents before retreating. Tubo army still maintained the initiative in their operations on the eastern border (present-day northwest China).

In the 9^th month of the lunar calendar, the governor of Yanzhou, Du Yanxian, abandoned the city of Yanzhou, which had been under construction for eight years, and fled to Qingzhou. This indicates that the city of Yanzhou, built in 793 AD, had been threatened by Tubo army after only eight years, causing the Tang garrison troops to abandon the city without fighting.

In order to ease the tension in the northern border, the Tang Dynasty ordered Wei Gao led his troops to penetrate deep into Sichuan to divide the Tubo forces. Wei Gao sent 20,000 troops in nine divisions to advance, and Nanzhao kingdom also assisted the Tang army. Wei Gao's troops attacked Tubo-occupied Weizhou, Baozhou, Songzhou, as well as Qiji City and Laoweng City. They defeated the Tubo army in Yazhou (west of Ya'an County, Sichuan), achieving great success. "Having crossed a thousand miles, they captured seven cities, established five military towns, burned down over 150 fortresses, beheaded over 10,000 enemies, and captured 6,000 prisoners and 3,000 defectors. They then besieged Weizhou and Kunming City." The Tang Dynasty bestowed upon Wei Gao the title of Marquis of Nankang County.

During the battles between the allied forces of the Tang Dynasty and Nanzhao kingdom against Tubo army, soldiers from the countries of Kang and Abbasid Caliphate countries from Central Asia were captured among the Tubo army. It was believed that these captured soldiers from Kang and Abbasid Caliphate were likely prisoners acquired by Tubo army in their wars against Western Asia and Abbasid Caliphate, who were then transferred to the eastern front of Tubo dynasty to fight against the Tang Dynasty.

In 802 AD, during the 9^th month of the lunar calendar, Wei Gao, the military governor of the southwest region of the Tang Dynasty, launched an attack on Weizhou (now,Zagunao Town, Li County, Sichuan). To relieve the siege of Weizhou, the Tubo Empire mobilized 100,000 troops led by Lun Mangre to march south from Lingzhou (now, Lingwu City, Ningxia province) and Shuozhou （now, the northeast of Shuozhou city, Shanxi province） where they were originally attacking the Tang Dynasty. Wei Gao, led Tang armies along with Nanzhao army, lay in ambush at a strategic location and lured the Tubo army into a trap. Tubo general Lun Mangre and his army fell into the ambush and over half of his soldiers were killed and Lun Mangre himself captured by the Tang army. He became the highest-ranking Tubo general captured by the Tang Dynasty.

The Nanzhao army played an important role in this battle. However, the Tubo garrisons in Weizhou (also known as Wuyou City) and Kunming City defended stubbornly, and Wei Gao's repeated attacks were unsuccessful, forcing him to retreat. This battle dealt a heavy blow to the Tubo Empire's influence in present-day Sichuan and its sourrounding. Lun Mangre was sent to Chang'an City, and the Tang Dynasty "granted him a residence in Chongrenli."

Most of the Tubo army consisted of cavalry, skilled in charging and attacking on open plains. However, the southwestern region of Tang dynasty was characterized by high mountains and deep valleys, making it difficult for cavalry to make significant progress. In addition, the Tubo forces initiated the attack, allowing the Tang and Nanzhao armies to block them using the advantage of the terrain. Therefore, the Tubo Empire found it difficult to make any gains.

Note 1: From 798 AD to 802 AD, for a period of five years, the Tubo Empire launched annual attacks on the Tang Dynasty. In particular, in 801, their military actions reached their peak, capturing Linzhou and Yanzhou. The frequency of these military actions against the Tang Dynasty seems inconsistent with the vigorous promotion of Buddhism within the Tubo dynasty by King Tride Songtsen. However, upon reviewing the Buddhist political practices of his father, King Trisong Detsen, it becomes clear that Tride Songtsen not only inherited his father's policy of promoting Buddhism but also followed his father's approach of simultaneously promoting Buddhism while engaging in military actions externally.

Note 2: "Zizhi Tongjian": "Tubo sent their Grand Minister, who also served as the military governor of the five eastern border districts, Lun Mangre, with a hundred thousand troops to lift the siege of Weizhou. The soldiers of Xichuan of Tang dynasty, stationed at strategic positions, set up an ambush to wait for them. When the Tubo troops arrived, they sent out a thousand men to challenge them. The enemy pursued them with their entire force, and at the ambush's signal, the enemy suffered a major defeat, with Lun Mangre captured and more than half of their troops killed or injured." The Battle of Weizhou between the Tang army and Tubo army marked the complete end of Tubo's raging attacks for over 40 years since the "Anshi Rebellion." It also meant that Tubo's economic resources, which relied on plundering Hexi and Longyou, disappeared as a result.

In 803 AD, Tubo dynasty took the initiative to adopt peaceful diplomacy due to military failures.

In the 4^th month of the lunar calendar, Tubo dynasty sent diplomatic envoys to the Tang Dynasty, and the Tang Dynasty accepted the Tubo delegation, thus restoring diplomatic relations that had been severed for 17 years.

In the 6^th month of the lunar calendar, the Tang Dynasty sent General Xue Bin as an envoy to Tubo dynasty. This meant that the Tang and Tubo had restored diplomatic relations in the year 803 AD and began exchanging envoys and communication.

In the book "The Feast of the Wise", it states, "In the year of the Water Yin Sheep (803 AD), Darma Udumtsan was born with a physique resembling that of a yellow ox. Because of his stupidity and arrogance, the people called him Lang Darma."

In 804 AD, a friendly atmosphere began to appear along the long ancient Tang-Tubo road.

In the 3^rd month of the lunar calendar, the Tubo envoy came to the Tang Dynasty to inform that the father of the current emperor, King Trisong Detsan, passed away in the fourth month of 13^th year of the Zhenyuan era (797 AD). They also conveyed the news of the death of the older brother of the current emperor, the former king Mune Tsanpo, in the 14^th year of Zhenyuan era (798 AD). Emperor Dezong of Tang dynasty ordered officials of the third rank or higher to receive the envoys and mourn for three days as a sign of condolence.

In the 4^th month of the lunar calendar, 54 people, including Zang Henan and Lun Qiran, came to the Tang Dynasty as envoys from Tubo dynasty. Among them, Tsenpo Nampo Techibo was also a member of the mission, indicating that Tubo's group of monks was committed to peaceful diplomacy.

In the 5^th month of the lunar calendar, the Tang Dynasty appointed Zhang Jian, the Deputy Minister of the Ministry of Works and Imperial Censor, to go and offer condolences to Tubo dynasty, in response to Tubo's visit to offer condolences. At the same time, General Xue Ren was appointed as the Acting Minister of the Ministry of Works, General of the Left Guard, and Imperial Censor, and was sent to Tubo as envoy in response to the arrival of Tubo's envoy, Lun Qiran.

In the 12^th month of the lunar calendar, another group of Tubo envoys, Lun Xire and Guo Zhichong, arrived in Chang'an. The latter was clearly a Tang person serving in Tubo.

In 805 AD, in the 2^nd month of the lunar calendar, Emperor Tang Dezong of the Tang Dynasty passed away, and Tang Shunzong ascended the throne. He ordered Tian Jingdu, the "General of the Left Guard, and Imperial Censor", to go to Tubo dynasty to inform the death of Tang Dezong, togher with Xiong Zhiyi, an official of the Ministry of Works and Imperial Censor, as the deputy envoy."

In the 7^th month of the lunar calendar, Tubo dynasty sent envoys, including Lun Xino, to the Tang Dynasty to offer condolences.

In the 10^th month of the lunar calendar, Tubo dynasty sent Lun Qiluo Bozang to the Tang Dynasty, bringing gold, silver, clothes, cattle, horses, and other items to assist in the construction of Emperor Tang Dezong's tomb.

In the 11^th month of the lunar calendar, Tang dynasty sent envoys to Tubo to inform about the changes such as the enthronement of the new king.

This year, it was a year of great friendship between the Tang Dynasty and Tubo Dynasty. The envoys from both sides frequently traveled on the well-connected roads. In this year, Wei Gao, a powerful official in the southwest region of the Tang Dynasty, passed away.

In 806 AD, in the 1^st month of the lunar calendar, the Tang Dynasty returned 17 prisoners who had been exiled to Fujian province to Tubo dynasty. Tang Dynasty usually exiled Tubo prisoners to Lingnan (It is a collective term for the area south of Wuling in southern China, namely Guangdong, Guangxi, Hong Kong, Macau and the entire territory of Hainan) to make the people from the cold and high-altitude regions endure the torment of a hot climate. This return of 17 prisoners was a selective act, intended to demonstrate the Tang Dynasty's willingness to reconcile with Tubo dynasty.

In the 6^th month of the lunar calendar, Tubo sent Lun Bocang as an envoy to the Tang Dynasty.

In the same year, Tritsu Detsen was born.

In 807 AD, in the 8^{th month of the lunar calendar, Tubo dynasty released 450 people, including Sengwei Liangchan, to the Tang Dynasty.}

In 808 AD, an event occurred where a subordinate tribe of Tubo dynasty, the Shatuo tribe, surrendered to the Tang Dynasty. Initially, after being captured by Tubo dynasty, the Shatuo tribe was resettled in Ganzhou (now, Zhangye city, Gansu Province). The Shatuo tribe was known for its strength and bravery among the various tribes in the northwest. In the wars started by Tubo dynasty, the warriors of the Shatuo tribe often served as the vanguard. Later, Tubo became suspicious of a connection between the Shatuo tribe and the Uighurs and decided to relocate the Shatuo tribe.

Upon learning of this, the leader of the Shatuo tribe, Zhuxie Jinzhong, along with his son Zhiyi, made the decision to pledge allegiance to the Tang Dynasty. With a tribe of 30,000 people, they traveled eastward from Wudejian Mountain (northeast of Ganzhou city, Gansu Province). Tubo dynasty, upon hearing the news, sent cavalry to pursue them. The soldiers of Tubo fought the Shatuo tribe several times, and Zhuxie Jinzhong was killed by Tubo's army. The Shatuo tribe suffered heavy losses, with the majority of their soldiers dead or injured. However, Zhiyi, with great resilience, led the remaining ten thousand people to surrender to the Tang Dynasty in Lingzhou (now, Lingwu City, Ningxia province). The Tang Dynasty resettled the Shatuo tribe in Yanzhou (now, Dingbian County, Shaanxi province)

In the same year, the Uighur Khanate's army captured Liangzhou (now Wuwei, Gansu Province). The Tang Dynasty decided to build the city of Linjing to defend against Tubo's invasion.

In 809 AD, the Tang Dynasty dispatched Xu Fu, an official from the Ministry of Rites, as an envoy to Tubo Dynasty. He brought a letter from Emperor Tang Xianzong to the Tubo Monk Prime Minister. The letter first praised the virtues of the Monk Prime Minister and his efforts for peace, and then mentioned the border issues between the two sides. Since the breach of the peace treaty in Pingliang, there had been a lack of clear boundaries and agreements between the Tang Dynasty and Tubo Dynasty. Tubo Dynasty had previously proposed returning the three provinces of Qin zhou, Yuan zhou, and Anle zhou (northeast of Tongxin County, Ningxia province) to the Tang Dynasty but due to various reasons, the negotiation did not succeed. The Tang Dynasty hoped that after the three provinces were returned to Tang control, a new treaty could be established. Lastly, the letter requested the release of Tang officials who were detained during Tubo Hijacks "Alliance Meeting" in Pingliang

In the 9^th month of the lunar calendar, 50,000 Tubo cavalry arrived at Futiq Spring (northwest of Hanggin Qi, Inner Mongolia), while over 10,000 cavalry went to Dashigu, plundering the Uighur envoys who were returning from the Tang Dynasty. This military action by Tubo was purely targeting the Uighur envoys traveling to the Tang Dynasty.

In 810 AD, in the 5^th month of the lunar calendar, the Tubo minister Lun Sixie was sent to the Tang Dynasty as envoy, he brought back the coffins of two Tang ministers, Lu Mi and Zheng Shuju.

In the 6^th month of the lunar calendar, Tubo envoys and Tang Prime Minister Du You held discussions. once again Tubo dynasty expressed their willingness to return the territories of Anle zhou, Yuan zhou, and Qin zhou

In the 7^th month of the lunar calendar, Li Xin, the Acting Censorate Chief of Tang dynasty was sent to Tubo dynasty as envoy. From the continuous negotiations, it can be seen that both sides had not reached a consensus.

In the same year, on the northwest front of Tubo dynasty, The Tubo army launched an attack towards the west, targeting the Abbasid Dynasty.

In 812 AD, Tride Songtsan granted another oath document to Myung Ting Ngejin, which was also engraved on a stone tablet, reiterating the previous achievements of Myung's. Myung Ting Ngejin appeared particularly cautious and unwilling to accept the grace bestowed by the emperor, perhaps fearing criticism from certain political enemies at court.

Tride Songtsan reiterated the validity of the previous oath document and specifically mentioned severe punishment for anyone plotting against or harming Myung Ting Ngejin, regardless of their identity. Additionally, it was mentioned that "no one has the right to interfere with the slaves, land, livestock, and other subjects offered to monasteries."

In the middle of this year, Tubo's army attacked Jingzhou (Now, the north of Jingchuan county, Gansu province), plundering people and livestock. At this time, Tubo dynasty and Tang Dynasty were in a period of peaceful diplomacy, making it difficult to explain Tubo's military actions. It could be attributed to small-scale incursions by Tubo's border troops.

Note: From the content of the two edicts granted by Tride Songtsan to Myung Ting Ngejin, it can be observed that the monks and monasteries had formed a powerful force in Tubo society, serving as a support for Tride Songtsan to counterbalance the power of the nobility and the imperial family.

In 813 AD, Tubo army attempted to build a bridge on the Yellow river within Huizhou (now, Jingyuan County, Gansu). However, whenever the wood for building the bridge was stored by the river, the local Tang Dynasty garrison secretly sent people to throw the stored wood into the river, preventing Tubo from constructing the bridge. Tubo then changed its strategy and bribed the greedy Tang Shuofang and Lingyan Jiedushi "Wang Bi" with abundant wealth, persuading them not to interfere with Tubo's construction of the Ulan Bridge on the Yellow River.

After completing the bridge, Tubo army built a fort called Yuecheng next to the bridge in order to guard this bridge which provided a shortcut for Tubo army to easily attack the Tang Dynasty. The risks of war remained, and the Tubo generals were still busy with military affairs.

In the 10^th month of the lunar calendar, the Uighur Khanate sent troops across the Gobi Desert, attacking Tubo army from the west of Liu Valley. Tubo dynasty and the Uighurs engaged in battle in the west of Liu Valley.

Note: During the reign of Tride Songtsan, Tubo dynasty also conducted large-scale military operations in the Western Regions. In the later period of Tride Songtsan's reign, Tubo's main opponents were the Uighurs, and there were periods of war and peace. In addition, the armies of the Abbasid Caliphate and Kangli also fought alongside Tubo, indicating that Tubo still had influence in Central Asia.

In 814 AD, according to the "Yuhé Erzhang," during the Year of the Horse (There were two Years of the Horse during the reign of Tride Songtsan, namely 802 AD and 814 AD, and the academic community generally believes that the movement to standardize translation practices began in the latter Year of the Horse, namely 814 AD), Tsena Medra and other Buddhist scholars were ordered to establish principles and methods for the translation of Buddhist scriptures, as well as to revise and update old translations of Buddhist texts.

Standardized translated names were established, and it was mandated that new translations of Buddhist scriptures must be translated according to the new standardized names. No one was allowed to create new words on their own. If the monastery or translation center needed to create new vocabulary, it must be agreed upon by the Khenpo (monastery abbot) and translators, and then submitted for approval by the Emperor before the new words could be used.

In the same year, the Abbasid Caliphate's Caliph Ma'mun attacked Wakhan and Bruzha, which were under Tubo control, capturing a Tubo commander and Tibetan cavalry and bringing them back to Baghdad.

Note: The standardization and regulation of translated names improved the quality of scripture translation, allowing Tibetan language to accurately express profound Buddhist doctrines. At the same time, it also improved the Tibetan language itself, promoting its dissemination and application, and had a positive impact on the development of Tibetan culture. With the strong support of Tride Songtsan, Buddhism spread extensively in Tubo.

In the year 815 AD, Tubo's request to establish mutual trade market with the Tang Dynasty was accepted.

In the same year, Tubo's King Tride Songtsan passed away after a reign of nineteen years at the age of forty. A stone stele was erected in front of his tomb, engraved with wonderful words praising Tride Songtsan's accomplishments and virtues. His son, Tritsu Detsen, succeeded him.

When Tritsu Detsen ascended to the throne (reign from 815 AD - 836 AD ?), there was a peaceful and smooth transition of power without any disturbances. This was a rare achievement in Tubo dynasty's history, indicating that Tride Songtsan was able to effectively control Tubo's political affairs, especially the tricky issues of the relationship between the native religion and Buddhism, as well as conflicts within different Buddhist sects. He appointed Buddhist monks as prime ministers, granting them significant power, thus avoiding the dilemma of mistrust between the ruler and his ministers.

Note: During Tride Songtsan's reign, there were three different the first prime ministers, namely "Brotri Zuramsha", "Basmang Je Ilod", and "Brozhangtri Sumje Tagnang". However, the early positions of "Branka Yontan" and "Myang Ting Ngezin" remained unchanged. This signifies that during Tride Songtsan's reign, the real wielders of power were the Buddhist monks "Branka Yontan" and "Myang Ting Ngezin", indicating Tride Songtsan's ability to implement the will of the monarchy and govern with Buddhist principles.

By elevating the political status of Buddhist practitioners and aligning with the pro-Buddhist forces in the court, Tride Songtsan effectively suppressed the native religion and achieved positive results. This not only avoided chaos during the transition of power but also demonstrated relative stability in Tibetan society during the turbulent periods following his father's and brother's deaths.

During Tride Songtsan's rule, with Buddhist monks in power and Tubo facing internal conflicts and setbacks in expanding its borders, Tubo shifted towards peaceful diplomacy and improved relations with the Tang Dynasty. Although no formal treaty or resolution was signed, however, the interactions and discussions between Chide Songzan's reign and the Tang Dynasty laid the groundwork for future diplomatic initiatives.

In the year 816 AD, Tubo general Zhang Xuxin'er launched an unsuccessful attack on the Khaganate of Uyghur's capital, "Woluduobali."

In 817 AD, in the 4^th month of the lunar calendar, Tubo dynasty' envoy arrived in Tang dynasty to express condolences for Tride Songtsan's death. The Tang dynasty mourned for three days to show their grief, and Tang dynasty also sent Wu zhongqi and others as envoys to Tubo dynasty for mourning rituals. Wuzhongqi requested Tubo's prime minister to release the captured Tang officials Fu Yu Zhun and Li Chan whom had been held captive by Tubo dynasty for thirty years and were currently herding livestock. With the improved relations between Tubo and the Tang Dynasty, Tubo dynasty agreed to release the two officials.

In 818 AD, in the 9^th month of the lunar calendar, a Tubo envoy named Lun Duan Lican was sent to Tang Dynasty, expressing Tubo's desire for friendship with Tang dynastgy. However, Lun Duan Lican had not yet returned to Tubo dynasty when conflicts erupted between Tubo and the Tang Dynasty.

On the 12^th day of the 10^th month of the lunar calendar, Tubo launched their first attack on Youzhou (now northeastern Etok Qi, Inner Mongolia). Tang army stationed in Lingzhou (now, Lingwu City, Ningxia province) counterattacked and launched an offensive against the Tubo army, defeating them and caused a loss of 20,000 soldiers of Tubo army.

On the 14^th day of the 10^th month, the Tang army led by Hao Hu, stationed in Pingliang Town, voluntarily launched an attack on Tubo army, defeating them and reclaiming the Yuanzhou ((now Guyuan County, Ningxia)), which had been occupied by Tubo dynasty. At the same time, the Tang military commander Tian Jin led his troops to defeat 3,000 Tubo soldiers in Lingwu.

On the 1^st day of the 11^th month, the Tang army in Xiazhou (now,Baichengzi town, in the northeast of Jingbian County, Shaanxi) defeated 50,000 Tubo soldiers. The Tang army in Lingzhou also captured Luo Cheng, a city west of the Changlezhou (now, west of Dingyuan City), which was held by Tubo.

On Tubo's southern front, Tang's military commander Wang Bo led the Tang army to recapture the cities of Ehe (north of Maowen County, Sichuan) and Qizhou (Qi). The Tubo army suffered continuous defeats.

At the same time, Emperor Xianzong of Tang dynasty decided to detain Tubo envoys.

In 819 AD, the Tang Dynasty released the Tubo envoy Lunduan Lican, who had been temporarily detained.

In the 8^th month of the lunar calendar, Tubo army launched an attack on Qingzhou (now, Qingyang city, Gansu province).

In the 10^th month of the lunar calendar, Tubo's Prime minister, Shang Trisumje, led his deputy, Zhang Tsepong Ihazang lupal, Tubo's Eastern Dao military commander, Lun Sanmo, and a total of 150,000 soldiers, along with the troops of the Tangut, besieged Yanzhou City (now, Dingbian County, Shaanxi province) which the defense works were rebuilt by the Tang Dynasty several times, Tubo army attacked this city from all sides with flying ladders, movable towers, and wooden donkeys.

Under the fierce attacks of the Tubo army, Yanzhou City was on the verge of collapse several times. However, the military governor of Yanzhou, Li Wenyue, led his troops to resist stubbornly. When the city walls were breached, they immediately dismantled houses and rebuilt the defense works. They defended day and night, preventing the Tubo army from capturing Yanzhou City. Later, General Shi Jingfeng of the Shuofang Army arrived with 2,500 soldiers in Tubo's rear, causing the Tubo army besieging Yanzhou City to retreat. The Battle of Yanzhou lasted for twenty-seven days.

According to "Cefu Yuangui·Generals and Commanders" in the 14^th year of Yuanhe of Emperor Xianzong of Tang (October), it was recorded that General Shi Jingfeng achieved a great victory over Tubo at the besieged Yanzhou City and mentioned, "In the 14^th year year of Yuanhe (819 AD), the Western barbarians frequently violated the border."

In 820 AD, in the 1^st month of the lunar calendar, Emperor Tang Muzong ascended to the throne of the Tang Dynasty. He sent envoys to inform Tubo Dynasty of his succession, and Tubo Dynasty also sent envoys to mourn the deceased emperors of the Tang Dynasty and congratulate the new emperor.

In the 2^nd month of the lunar calendar, Emperor Tang Muzong issued a general amnesty and ordered the release of Tubo prisoners who had been exiled to various places, returning them to the Tubo Kingdom. When the Tang envoy Tian Ji arrived in Tubo dynasty, the Tubo requested a meeting with Tang dynasty at Changwu City (now, northwest of the Jing River in Changwu County, Shaanxi province). Tian Ji, being timid and fearing that he would not be able to return to Tang dynasty if he didn't comply with Tubo's request, only nodded in agreement, but in reality, he did not have the authority to decide.

In the 2^nd month of the lunar calendar, the Tubo army attacked Lingwu (now, Lingwu City, Ningxia province).

In the 3^rd month of the lunar calendar, the Tubo army attacked Yanzhou (now, Dingbian County, Shaanxi province).

In the 10^th month of the lunar calendar, with the assistance of the Tangut, the Tubo army entered the territory of Jingzhou (Now, the north of Jingchuan county, Gansu province) and the army was so large that it camped last over 25 km long. Tubo's aim was to directly attack Changwu City, claiming that it was because Tian Ji agreed to the meeting. The Tang Dynasty received the alert of Tubo's invasion and immediately sent troops to rescue Jingzhou. However, the Tubo army didn't engage in battle with the Tang army and instead retreated, entering the territory of Yanzhou and setting up camps near Wu-chi (in Dingbian County, Shaanxi) and Bai-chi (also in Dingbian County). Later, over a thousand soldiers besieged "this two Chi" before retreating.

Note: Prior to the Chongqing Covenant (a peace agreement between Tubo dynasty and Tang dynasty), Tubo dynasty and Tang dynasty had held several meetings, but they did not bring long-term peace, but only temporarily eased the tense situation, and the meetings became a means of truce. Both Tubo dynasty and Tang dynasty had extremely strong military forces, and their border commanders were greedy for glory, leading to mutual plunder and killings. They remained highly vigilant towards each other. "The covenant proposed by the Tubo dynasty and Tang dynasty was not established, and grievances emerged. This was because of the turbulence between them in the past. Suspicion and doubt led to the delay of the Great Peace Covenant. Suddenly, deep enmity arose, and they were about to face each other in war, becoming enemies."

Due to past grievances and mutual distrust, but since the reign of Tride Songtsan, Tubo gradually slowed down its pace of military aggression towards foreign erritories, especially during the period of Tritsu Detsen (also known as Tri·Ralpacan). Tubo dynasty had more confidence in peace. The Tubo dynasty was aging, especially within the ruling class, which started to decay with many internal contradictions. Tritsu Detsen and his ministers tried to maintain the functioning of the dynasty and did not have the energy to invest in war. The continuous external attacks throughout the generations also wasted a great deal of resources and manpower. While the war filled the treasure trove of the king with gold, silver, and precious items, the sacrifices and burdens borne by the lower-class common people became increasingly significant, and the sentiment of war weariness spread throughout the land of Tubo dynasty.

Tubo dynasty used forced military means to achieve the occupation and rule of Longyou, Hexi, Western Regions, and other territories. However, the people living on the occupied land by Tubo dynasty could not help but constantly yearn for their homeland. For Tubo dynasty, how to effectively govern and maintain control over these already occupied areas, eliminate ethnic conflicts, became the most challenging and urgent matter. Additionally, with the ruling class of Tubo dynasty being dominated by the monks, who adhere to the compassionate spirit of Buddhism and oppose war, and with Tritsu Detsen obediently following the policies of the monks, all of these factors led Tubo dynasty to change its foreign policy and adopt a strategy of peaceful diplomacy. At this time, the Tang Dynasty was also declining from its strong position, with eunuchs controlling the court, regional warlords asserting their independence, and the government becoming increasingly corrupt and powerless in external military actions. The historical backdrop of both sides' continuous decline made it easier for them to reach a lasting peace agreement with each other.

In 821 AD, Liu Yuanding, an envoy from the Tang Dynasty, was sent to Tubo Dynasty. Upon his arrival, Tubo's King, specially arranged a literary and artistic performance to express their welcome.

In the 4^th month of lunar calendar, Tubo dynasty dispatched Zhang Qili Tose to the Tang Dynasty, bearing a letter of the king of Tubo dynasty expressing their desire to hold a meeting and establishing an alliance with the Tang Dynasty.

In the 6^th month of lunar calendar, Tubo army launched an attack on the Qingse Fortress in the Tang territory but was repelled by the Tang general in Yanzhou (now, Yan'an city, Shaanxi Province).

In the 8^th month of lunar calendar, Tang dynasty and Tubo dynasty held the first meeting at Wanghui Temple, located in the western outskirts of Chang'an (now, Xi'an, Shaanxi Province).

In the 9^th month of lunar calendar, Tubo dynasty sent a higher-ranking official, Lun Naro, whose official title in Chinese historical records was Minister of Rites. This high-ranking Tubo official brought the alliance treaty signed by the Tibetan King and the chief monk prime minister, to participate in the meeting in Chang'an. Emperor Muzong of the Tang Dynasty attached great importance to this meeting.

In early of the 10^th month of lunar calendar, fourteen officials of Tang dynasty, including Prime Minister Cui Zhi, held a meeting with the Tubo envoy Lun Naro at Wanghui Temple in the county seat.

On the 10th day of the 10^th month of lunar calendar, the Tubo envoy met with senior ministers of the Tang Dynasty in front of Xingtang Temple in the western corner of the capital. The names of the 17 Tang's officials who participated in the meeting were recorded in the agreement. Although the agreement did not explicitly define the borders between Tang dynasty and Tubo dynasty. However, it is evident from the alliance's statement from the Tubo side that they clearly advocated maintaining the status quo.

In 822 AD, Tang Dynasty appointed Liu Yuanding, the Imperial Censorate Grand Preceptor, as the envoy for the Tang-Tubo alliance, with Liu Shilao, the Deputy Minister of the Ministry of War and Imperial Censor, serving as his deputy. They entered Tubo together with the Tubo envoy Lun Naro

On the 24^th day of the 4^th month of lunar calendar, Tubo dynasty warmly received the envoy from the Tang Dynasty. The young King, Tritsu Detsen, received Liu Yuanding and his entourage in his heavily guarded and splendid royal tent.

On the 6^th day of the 5^th month of lunar calendar, Tubo conducted a grand alliance meeting with the Tang envoy at the East Zhedui Garden in Lhasa, where a meeting altar (ten steps wide and two feet high) was built.

In the 6^th month of lunar calendar, Tubo's army attacked Lingwu (now, Lingwu City, Ningxia province), Yanzhou(now,Dingbian County, Shaanxi province),

In the 8^th month of lunar calendar, 180 people who were originally captured and brought to Tubo dynasty were sent back by Tang troops in Fengxiang (now, it belongs to Baoji City, Shaanxi Province). Emperor Tang Muzong issued an imperial decree to the Jingzhao Prefecture to conduct a detailed investigation and identify their relatives, allowing them to return their home. This seems to be Tubo releasing the captives to the Tang Dynasty's Fengxiang military governor, who then sent them to the capital of Tang dynasty.

Note 1: From 821 AD to 822 AD, The 8^th alliance meeting took place during the reign of Emperor Tang Muzong, specifically from the first to the second year of the Changqing era. Therefore, this alliance is also known as the "Changqing Alliance". Tubo king Kali Kochu (this is the Chinese appellation for the Tubo ruler Tritsu Detsen) built the Changqing Alliance Monument at the entrance of the Jokhang Temple in Lhasa. The inscription on the Changqing Alliance Stele states: "The "Uncle" and "Nephew" rulers discussed state affairs as one, established a great and unchanging alliance, and vowed everlasting harmony." This established the "Two countries though, but one family" relationship between the Tang dynasty and Tubo dynasty.

Note 2: Tang Dynasty and Tubo Dynasty had significantly different interpretations of the terms "uncle" and "nephew" in the alliance document.

Note 3: From 705 to 822 AD, Tang Dynasty and Tubo Dynasty held a total of eight alliance meetings.

In 823 AD, in the 1^st month of Lunar calendar, Tubo dynasty sent an envoy to the Tang Dynasty .

On the 14^th day of the 2^nd month of Lunar calendar, a stone monument was erected in Lhasa to commemorate the alliance of Tang dynasty and Tubo dynasty. The alliance text was engraved on the monument, and Tang's officials also participated in the ceremony. A similar alliance monument was also erected in the capital city of Chang'an (now Xi'an, Shaanxi province) of the Tang Dynasty. The Tang-Tibetan Alliance Stone monument, erected in Lhasa, has withstood the test of time for a thousand years, still standing tall in front of the Jokhang Temple. The front of the stone monument is engraved with the alliance text in both Tibetan and Chinese, which is similar to the alliance text mentioned during the Xi'an Alliance meeting. The main contents are as follows:

(1) The "nephew" and "uncle" have established a great alliance for the well-being of the people, long-term peace and harmony, and the stability of the state.

(2) The east belongs to the Tang Dynasty, and the west belongs to Tubo Dynasty. The borders are delineated by each jurisdiction, and both sides shall not engage in warfare, release prisoners of war, and provide food and clothing.

(3) In terms of mutual exchanges, the old routes should be used as trade routes, and the horse market trade should be conducted in the buffer zone between the two sides, with the Tang Dynasty supplying the areas east of the "Suirong Palisade", and Tufan supplying the areas west of "Qingshui County."

(4) If one party violates the oath or the agreement, the other party has the right to take similar actions.

The boundaries in various areas were not clearly defined, but the Tang Dynasty tacitly accepted Tubo's occupation of Longyou and Hexi, which was Tubo's desired outcome.

The back of the alliance monument is entirely in Tibetan and describes the friendly relations between the Tang Dynasty and Tubo Dynasty, as well as the process and timeline of this alliance. Tritsu Detsen (also known as "Ralpacan"), the king of Tubo, also adopted the "Yitai" reign title, meaning "long-lasting peace and prosperity," which is the only reign title in Tubo's history.

After the Tang-Tubo Changqing Alliance was signed and completed in Lhasa of Tubo, Tang dynasty's representative of the alliance, Liu Yuanding, passed through Hexi on his way back to the Tang Dynasty. he and his men were welcome by Tubo's Prime Minister, Zhang kri Sumje, in Daxia Canyon. Zhang kri Sumje gathered more than a hundred generals from the eastern military regions and announced the alliance text on the platform, allowing the generals to read it. After a high-spirited recitation on the platform, they bound everyone to observe the border agreements and not to invade or plunder. This unprecedented gesture by Tubo showed their determination to abide by the Tang-Tubo Changqing Alliance. Indeed, after the year 822 AD, the continuous warfare on the Tang-Tubo border came to a sudden halt.

Since the Changqing Alliance, the border between the two sides has maintained peace for over twenty years, and there have been no major wars between Tang and Tubo.

In the same year, Tubo and Uighur also established a ceasefire alliance.

Note: After Tritsu Detsen assumed power in 823 AD, Tubo's state affairs deteriorated further day by day. According to the historical records of Tibetan Buddhism, Tritsu Detsen was assassinated by his subordinates.

In 824 AD, in the 1^st month of the lunar calendar, Tang Jingzong ascended the throne.

In the 2^nd month of the lunar calendar, Tang dynasty appointed Wu Si, the Palace Attendant Imperial Historian, as the envoy to Tubo dynasty to inform the death of emperor of Tang, and the new king of Tang dynasty. Tubo dynasty responded by sending consoling and congratulatory envoys.

In the 9^th month of the lunar calendar, Tubo dynasty sent envoys to request a map of Mount Wutai. At this time, Buddhism was flourishing in Tubo, and Mount Wutai was renowned as a site dedicated to Bodhisattva Manjushri. Hence, Tufan made this request.

In the 10^th month of the lunar calendar, Tubo dynasty sent envoys to Tang dynasty, presenting gold and silver artifacts that were crafted in Tubo. These included a silver rhinoceros, sheep, and deer.

In the 12^th month of the lunar calendar, Tubo dynasty sent envoys to Nanzhao (a kingdom in present-day Yunnan province, China). The gifts that Tubo dynasty presented to Nanzhao kingdom also included many gold and silver artifacts. According to the "Dehua Stele" of Nanzhao, it stated, "The Tubo king generously rewarded me for my merits and achievements. The prime minister accordingly ordered Zhan Yele to present a golden crown, brocade robe, golden belt, golden tent, bed, umbrellas, saddles, silver animals, and utensils." These gold and silver artifacts were a testament to the exquisite craftsmanship of Tubo artisans.

Note: Many Buddhist monasteries built by Tubo artisans featured various animal-shaped metal sculptures. For example, in front of the gates of the Samye Monastery, there were four stone steles, each adorned with four copper-cast dogs. The craftsmanship of these animal sculptures may have originated from the neighboring regions of Tubo, and the Tibetans adeptly mastered these techniques, including casting, forging, and gilding. Thus, Tubo's metalwork achieved remarkable acclaim at that time. Of course, some of the metal objects sent by Tubo to the Tang Dynasty may have come from Central Asia and South Asia, not exclusively produced in Tubo.

In 825 AD, in the 1^st month of the lunar calendar, Tang Muzong issued a general amnesty, demanding the release of Tubo prisoners who were exiled to various regions. Accepting surrender was prohibited, and capturing new prisoners was not allowed.

In the 3^rd month of the lunar calendar, Tubo envoy Zhang Qilire entered Tang dynasty.

In the 4^th month of the lunar calendar, Tubo's Liu Shinu surrendered to Tang army. Tang dynasty issued an edict to return him to Tubo dynasty. It is possible that Liu Shinu was a Han Chinese living in Tufan's territory.

In the 9^th month of the lunar calendar, Tang dynasty dispatched Li Rui, the supervisor of the Imperial Household, as an envoy to Tubo dynasty

In the 10^th month of the lunar calendar, Fu Chengkang was appointed as the deputy magistrate and chief censor, and he served as the congratulatory envoy to Tubo. He was also bestowed with a purple gold fish bag.

In 826 AD, Lingwu Military Governor of Tang dynasty received four surrounded individuals from Tubo army, including General Shi Jinshan. Tang dynasty ordered the local military chief to send them back to Tubo army.

In 827 AD, in the 1^{st month of the lunar calendar, Tubo Dynasty's Envoy, Lun Drongdare, was sent to Tang dynasty, bringing with him gold and silver objects, jade belts, and horses to congratulate Tang Wenzong on his ascension to the throne.}

In 828 AD, in the 12^th month of the lunar calendar, Tang dynasty sent Ju Yu Fu and Tang Hongshi, who held the position of Imperial Censor, as envoys to Tubo dynasty to express gratitude for Tubo dynasty's congratulatory envoy.

In 830 AD, Tang Dynasty minister Li Deyu's memorial mentioned, "Nanzhao kingdom sent 2,000 captured Tang people from Shu state and offered gold as tribute to Tubo dynasty," proving that Tubo dynasty and Nanzhao kingdom had started to establish communication during the Tritsu Detsen reign.

In the 12^th month of the lunar calendar, Tubo's envoys entered Tang dynasty, and Tang dispatched Li Congyi, a deputy minister of the Ministry of Rites, as a response to Tubo's congratulatory envoy.

After the Changqing Alliance, the envoys from both sides frequently traveled between Tang dynasty and Tubo dynasty, the relationship between Tang dynasty and Tubo dynasty reached an unprecedented level of closeness.

In 831 AD, in the 1^st month of the lunar calendar, Tubo dynasty sent envoy to discuss the exchange with Tang Dynasty.

In the 9^th month of the lunar calendar, the "Weizhou Incident" occurred. At that time, Li Deyu, the military governor of Xichuan of Tang Dynasty, actively administered the border regions to prevent Tubo army and Nanzhao army from causing trouble.

In the same year, Tubo Dynasty used a large amount of money to hire workers from Khotan and Nepal to construct the magnificent “Ushang lakhang/”(also known as Von-cang-do lakhang) on the middle reaches of the Lhasa River (now, in Tsana Township, Qushui County). This monastery had nine majestic levels and was considered one of the masterpieces in the architectural history of the Tubo Dynasty. Its lower three levels were built with stones, the middle three levels with bricks, and the upper three levels with wood.

Note: During the reign of Tritsu Detsen, numerous monasteries were also built by the Tubo Dynasty in territories they occupied, including the Hexi region. Among the remaining 492 caves in the Dunhuang Mogao Caves, more than 40 can be confirmed to have been built during the Tubo occupation period, and with the majority of them constructed during the reign of Tritsu Detsen.

"Weizhou Incident"

In the 9^th month of the lunar calendar, the deputy commander of the Weizhou region of Tubo Dynasty, "Xi damu," sent trusted individuals to contact Tang army that "Xi damu," voluntarily proposed to surrender the army he led and Weizhou city to Tang Dynasty, which was a great success for Tang Dynasty

Weizhou City (now Zagunao Town, Lixian County, Sichuan Province) was a vital military fortress, also named "Wuyou City", meaning "Worry-free city, by Tubo Dynasty. The Tang general Wei Gao had used various strategies but failed to capture it. "Wuyou City" remained firmly under the control of Tubo army, which was a lifelong regret for Wei Gao. Unexpectedly, this Tubo military commander, "Xi damu", for unknown reasons, prepared to hand over Wuyou City without a fight. This was something that Tibetan King Tritsu Detsen and his ministers did not anticipate, and it was also something that the Tang generals had longed for but never expected. Li Deyu, the local chief military officer of Tang Dynasty fearing deception, sent someone to deliver a brocade robe and belt as further communication.

"Xi damu" promptly led his subordinates into Chengdu city. Tang general Li Deyu then dispatched Tang soldiers to guard Weizhou City, effortlessly reclaiming it for Tang Dynasty. Tubo lost an important military fortress, and the defending soldiers all surrendered to the Tang Dynasty. Undoubtedly, this made the Tubo dynasty had to admit that this matter was extremely painful, as the loss was not only a city but much more.

Tang general Li Deyu believed that from Weizhou City, "traveling northeast through the Yaosuo Congling Mountains for two hundred miles, the terrain is not treacherous, via Changchuan it is less than three thousand miles, straight to Tubo's heart." Therefore, he proposed to Tang dynasty to send three thousand Qiang tribe soldiers to burn down Tubo's thirteen bridges and strike at Tubo's vital points, delivering a fatal blow to Tubo dynasty. Many ministers of the Tang Dynasty strongly supported Li Deyu's bold plan, and even Emperor Tang Wenzong was deeply moved.

However, Li Deyu's political rival, Niu Sengru, disagreed. He pointed out that Tubo's territory stretched for thousands of miles in all directions, and losing one Weizhou City would not affect Tubo's power. Moreover, Tang dynasty and Tubo dynasty had just formed an alliance, so breaking it would be a breach of trust. Currently, Tubo's horses were grazing in Wei-ru-chuan. If Tubo were to send troops eastward, they could reach Xianyang Bridge in just three days. At that point, even if they gained hundreds or thousands of "Weizhou Cities," what use would it be? These words startled the emperor of Tang dynasty and changed his thoughts, thus altering the fate of Xi damu and his subordinates. Emperor Tang Wenzong issued a decree for Li Deyu to return the Tubo soldiers and Weizhou City to Tubo dynasty. Helpless, Tang general Li Deyu had no choice but to comply. Xi damu and his subordinates, who had set off happily for Chengdu, were caught off guard by this twist of fate. They embarked on their journey back with feelings of despair, fear, and sadness. Tubo's harsh laws left them without a glimmer of hope. The Tubo generals deeply resented the actions of Xi damu and this subordinates, and they executed them all on the border between Tang dynasty and Tubo dynasty before departing, reclaiming Weizhou City once again.

In 832 AD, in the 11^th month of the lunar calendar, A envoy was sent by Tang Dynasty serving as the official congratulatory envoy to Tubo dynasty. He was also bestowed a purple-gold fish bag.

In the same year, Yuthog Yonten Gonpo passed away at the age of 125. He was later honored as the "Saint of Medicine," "Medicine King," and the "Ancestor of Tibetan Medicine" by later generations.

Yuthog Yonten Gonpo

Among the native doctors of Tubo dynasty, the most well-known and revered figure in later generations was "Yuthog Yonten Gonpo." Yuthog was born into a family of Tibetan doctors in Duilong. His father, Yutuo Chungpo Dorje, and his mother, Gyapa Chudzin, provided him with a good family education and instilled in him a love for medicine from an early age. He was also intelligent and eager to learn. By the age of twenty, he had already achieved significant accomplishments in the field of medicine. However, he was never satisfied with his knowledge and constantly sought guidance from renowned physicians, humbly learning from them. He also traveled abroad to study, displaying great determination and a thirst for knowledge. He went to India three times to study the medical arts of the Indian subcontinent, and also visited various places such as Mount Wutai in the interior and the Qinghai-Tibet Plateau, greatly enriching his medical knowledge.

Later, he became the imperial physician of Trisong Detsan, treating patients, conducting medical research, writing books, and attracting numerous students, nurturing thousands of Tibetan medical talents.

Yuthog spent twenty years compiling a groundbreaking classic in the history of Tibetan medicine called "The Four Medical Canons." The book is divided into four parts: -1), the fundamental medical canon which includes discussions on the physiology, pathology, diagnosis, and treatment of diseases related to the human body; -2), the discourse medical canon which discusses human physiology, anatomy, etiology, pathophysiology, disease progression, treatment principles, and external medical instruments; -3), the secret medical canon which discusses methods for the diagnosis and treatment of various diseases; -4), and the subsequent medical canon which discusses pulse diagnosis, urine diagnosis, the functions and preparation of various drugs, as well as treatment methods such as moxibustion, bloodletting, and external application. The entire book consists of 156 chapters, totaling approximately 241,000 words.

"The Four Medical Canons" incorporated medical theories and treatment methods from India, the Tang Dynasty, and other regions, while also inheriting Tubo's own medical traditions, resulting in a comprehensive medical system. The book's descriptions and discussions regarding internal organs, human anatomy, and hygiene are fundamentally consistent with modern medicine. It records over a thousand types of medicines. "The Four Medical Canons" comprehensively elaborates on the theories and clinical treatments of Tibetan medicine, laying the foundation for Tibetan medical theory. Its publication marked the establishment of the Tibetan medical system.

Yuthog had a prolific writing career and authored over thirty medical works, including "The Lamp of Practical Experience," "Eighteen Original Medicines," "Pulse Diagnosis and Its Revelations," and "The Mirror of Anatomy." Yuthog also proposed a series of professional ethical principles, emphasizing the humanitarian spirit that doctors should uphold. He advocated for saving lives and promoting human health as the duty, while discouraging greed for money and emphasizing compassion and equality in treating the less fortunate. He also encouraged doctors to continuously strive for excellence and remain humble and eager to learn in their technical skills.

In 834 AD, in the 1^st month of lunar calendar, Li Tingjin, the governor of Fengxiang of Tang Dynasty, was sent to Tubo dynasty as an official envoy to deliver a congratulatory letter to Tubo king

In 835 AD, in the 1^st month of lunar calendar, Tibet dispatched an envoy named Lun Longre to Tang Dynasty.

In the 11^th month of the lunar calendar, Li Congjian, the Deputy Chief Censor, was appointed as an envoy to Tubo to respond to their congratulations. He was also awarded a golden fish bag by Tang dynasty's emperor

In 838 AD, Tritsu Detsen, who was the Tibetan Emperor, was sunbathing in the garden while drinking alcohol. When he became heavily intoxicated, he was murdered by three ministers who opposed Tibetan Buddhism. The ministers were named Dab Gyal Tore, Coro ledra and Le dutsan. Tritsu Detsen was 36 years old at the time of his death. After Tritsu Detsen's death, his brother, Damar, ascended to the throne as the ruler of Tubo. His honorary title was "U Dumtsan" (some sources claim that Damar succeeded to the throne in 836 after Tritsu Detsen's death).

In the 12^th month of lunar calendar, the Tang Dynasty dispatched Li Jingru, the Deputy Chief Imperial Censor, to Tubo as the envoy for mourning and congratulatory.

Note 1: Some sources say Tritsu Detsen passed away in 836 AD and his younger brother Damar (also "Damo") succeeded him. "Damo" was the transliteration in Tang Dynasty, and it is now translated as "Damar". Tibetan historical books also refer to him as "Lang Damar". "Lang" refers to a yellow ox, and according to "The Feast of the Wise", "Lang Damar" was known for his dull and stupid nature like an ox, hence the nickname "Lang Damar", which is derogatory. Lang Damar is often criticized and ridiculed in later Tibetan historical writings.

Note 2: Tritsu Detsen was born in 806 AD and died in 836 or 838. The king, Tritsu Detsen, drank rice wine and fell asleep in the garden. Three ministers who opposed Tibetan Buddhism twisted his neck, forcefully twisted his head on his back, and Tritsu Detsen died. Tritsu Detsen's administration and actions had failed to win the hearts of the people, leading to his assassination.

Note 3: It is known that under the rule of Tritsu Detsen, Tubo's power declined. According to the "New Book of Tang·Tubo Biography", it is recorded that "the Tibetan Emperor (Tritsu Detsen) has been in power for about thirty years, being sick and not able to handle state affairs, he left it to his ministers, so Tubo dynasty was unable to resist Tang dynasty and could only hope for peace on the border." The "Zizhi Tongjian" also records that "Yitai (Tibetan Emperor) was often ill and entrusted the government to his ministers, resulting in self-defense and long-term absence of border troubles." The above-mentioned sources from the "Wenzong Shilu" (Records of Emperor Tang Wenzong) mention Tritsu Detsen's health conditions as "sick and unable to handle affairs", "suffering from various illnesses", and having "heart disease". According to common sense, it is unlikely for someone who is weak and sickly to have ambitions for external expansion, and Tritsu Detsen is no exception.

Note 4: After the Changqing Alliance, both the Tang Dynasty and Tubo Dynasty sent envoys to each other. Tubo Dynasty sent a congratulatory envoy, which usually arrived in Tang in the first or second month and returned to their country in the second or following month. On the other hand, Tang Dynasty dispatched a "reply to congratulatory envoy" to Tubo dynasty in October, November, or December, These envoys of Tahng dynasty were all appointed with the important titles of Imperial Censor or Deputy Chief Censor. According to the above information, the exchange of congratulatory envoys between the Tang and Tubo dynasties began in the year 823 AD, after their Changqing Alliance in 822 AD, and continued until 836 AD, lasting for 14 years. This indicates that both sides followed the lunar calendar and customs, sending each other envoys during the Chinese New Year to express mutual blessings. The exchange of congratulatory envoys between the Tang Dynasty and Tibet is sufficient to illustrate that after the Changqing Alliance in 822 AD, both sides indeed showed goodwill, friendly interaction, until the Tibetan internal turmoil.

Note 5: The coronation time of Lang Damar

According to "The Feast of the Wise" Lang Damar ascended the throne in the year of Iron Rooster (841 AD) at the age of 39. He ruled for 6 years and was assassinated in the year of Fire Tiger (846 AD) at the age of 44. Historical records such as "Buddhist History: Dabaozanglun," "Han-Tibetan History Collection," and "Red History" all unanimously agree that Lang Damar ascended the throne in the year of Iron Rooster.

However, "Qing Shi" and "Records of the Tubo Kings" do not hold the same belief. "The Qing Shi" records: "In the year of Bingchen (836 AD), the Tibetan king passed away, and the throne was succeeded by his younger brother, Sa damo (Lang Damar), in the same year." "In the year of Xinyou (841 AD), Langdama's reign came to an end. In that year, Lang Damar destroyed Tibetan Buddhism and was immediately killed by Lhalung Palkye Dorje."

In Chinese historical records, "Zizhi Tongjian" and "New Book of Tang: Tubo Chronicles" mention, "In the second year of Huichang (842 AD), when the Tsanpo passed away, Lun Tsanre and others came to report, and Li Jing, the Director of the Bureau of Works, was ordered to mourn to Tubo dynasty." Considering the distance between Lhasa and Chang'an, it usually took the Tibetan envoys some time to reach Chang'an to convey mourning. This implies that the Tsanpo died in the first year of Huichang (841 AD).

However, some scholars believe that the "Tsanpo" mentioned in this account should be Tritsu Detsen, also known as "Ral pa can". If we follow this argument, and if Tritsu Detsen died in 841 AD, then the timing of Lang Damar's accession to the throne aligns with what is recorded in books like "The Feast of the Wise." However, there is an imperial edict in Tang history that is not often noticed. In the 3^rd month of the 4^th year of Huichang reign of Tang Wuzong (844 AD), Li Deyu, in his writing "Ci-yuan-bian-zhu-zhen-mi-zhou-yi" for Emperor Wuzong, mentioned, "It has been three years since Tubo has not established a King." If we go back three years from this time, the exact time for the passing of the Tsanpo lines up with the 2^nd year of Huichang reign (841 AD) when the Tibetan envoys departed to announce the mournful news.

If it was Tritsu Detsen who passed away at that time, then the "three years without an established Tsanpo" would make no sense. Therefore, the academic community generally agrees with the dating specified in Tang history, which is that Lang Damar was assassinated in 841 AD (the first year of Emperor Wuzong's Huichang reign).

This year -- 841 AD -- also marks the end of the Tubo dynasty.

In 839 AD, Tang Dynasty dispatched Li Jingru, the Prince's Advisor, as an envoy to Tubo dynasty which responded by sending an envoy back to the Tang Dynasty.

In 840 AD, the Uyghur Khaganate was defeated by the Karluk tribe, leading to the decline of the Uyghur Khaganate. The Uyghur tribes scattered, with some heading west to Geluolu, some fleeing to Anxi in Western region (now, Xinjiang). During this time, a portion of the Uyghurs surrendered and under the rule of Tubo dynasty

In 841 AD, Lang Damar ordered the prohibition of Tibetan Buddhism, known as the Great Buddhist Persecution. During this period, monasteries were destroyed, Buddhist scriptures were burned, monks and nuns were forced to return to laity or killed, and Buddhist statues and scriptures were vandalized. This led to a dark period for Tibetan Buddhism in the following centuries, marking the end of the "Snga dar (meaning "the first Propagation")" of Tibetan Buddhism from a religious development perspective.

In this year, a severe famine occurred in the Tubo Dynasty.

In the same year 842 AD, Lang Damar was shot and killed by the monk Lhalung Palkye Dorje whom was a general of Tubo army.

In the 12^th month of lunar calendar, the Tibetan envoy Lun Pure came to Tang dynasty to announce the death of Tsanpo Lang Damar, and the Tang Dynasty sent Li Jing as a mourning envoy.

As Lang Damar had no son, his brother's three-year-old son, Aangda Yumtan, was appointed as the Tibetan king. From this time on, Tubo dynasty entered a period of internal turmoil, with power struggles among the nobles to support their preferred prince. The Tibetan Frontier Defense Army, which bordered Tang Dynasty, fell into turmoil and unrest, culminating in the large-scale Battle of "Wu-yue (Du-Yor Drugpa)" five years later.

Death of Lang Damar

In 841 AD, Lhalung Palkye Dorje disguised himself and hiding a bow and arrow, he rushed towards Lhasa. When Tibetan king Lang Damar lowered his head to read the inscription on the Tang-Tubo Alliance Monument in Lhasa. Palkye Dorje, a warrior who had fought on the battlefield, drew his iron bow and shot an iron arrow, hitting his king between the eyebrows and the arrowhead became visible at the back of the neck. Lang Damar Tsanpo only uttered an enigmatic phrase: "Perhaps it should have happened three years earlier, or perhaps three years later." He then died on the spot. Afterward, Lhalung Palkye Dorje escaped and hid in the He-huang region (now, south of Xining city, Qinghai province). Lang Damar was the last unified ruler of the Tubo dynasty

In 842 AD, Tubo dynasty was embroiled in internal conflicts and unable to send envoys to Tang Dynasty, while Tang Dynasty, affected by the chaotic Tibetan Frontier Defense Army stationed near its border, was also unable to send envoys to Tubo dynasty. Communication between Tang Dynasty and Tubo dynasty ceased, and their diplomatic relations formally ended in this year.

In 843 AD, Lun Kongre continued his westward expedition but encountered a powerful opponent, Zhang Bi Bi, who belonged to the Dro clan, one of the prominent clans of Tubo Dynasty, also known as Zhang Sumje. Their ancestors held important positions in the Tubo Dynasty for generations.

In the 6^th month of lunar calendar, Lun Kongre led a large army to the west, preparing to attack the army led by Zhang Bi Bi. The "New Book of Tang·Tubo Chronicle" states that there were about two hundred thousand troops, along with a long train of pack animals and livestock, stretching for hundreds of miles. However, when they reached Zhenxi Army (180 miles west of Hezhou -- now Linxia Prefecture, Gansu Province), an unexpected strong wind suddenly arose, accompanied by thunder and lightning. Lun Kongre felt a sense of foreboding and decided to halt his troops.

Zhang Bi Bi knew that Lun Kongre looked down on him, so in order to deceive him, Zhang Bi Bi sent people to present gifts and commend Lun Kongre for his efforts in saving the country during a time of crisis. He expressed his willingness to obey Lun Kongre's command, stating, "I, Bi Bi, am dull-witted but fond of reading. When the Tibetan king bestowed a fief upon me, I truly felt unworthy and ashamed. I only wish to retire peacefully. If Your Excellency bestows me with a burial place, I will return to my field, fulfilling my lifelong aspiration."

Lun Kongre was overjoyed upon reading the letter and said to his generals, "Bi Bi only cares about books and has no knowledge of military strategy! When I become the ruler, I will appoint him as prime minister and have him sit in my home, without assigning him any tasks." With these words, Lun Kongre revealed his inner conspiracy. Afterward, he felt at ease and believed that Zhang Bi Bi was not a concern. He then led his troops back.

In the 9^th month of lunar calendar, Lun Kongre stationed his army in Daxichuan (now Xiahe, Linxia, Gansu Province). Zhang Bi Bi sent two generals, Pang Jiexin and Mang Luo Xue Lü, to lead fifty thousand elite soldiers to attack Lun Kongre. Zhang Bi Bi set up an ambush with forty thousand soldiers in a strategic position, while another ten thousand laid in wait in the Willow forest to the south of Hezhou (now Linxia Prefecture, Gansu Province). Pang Jiexin led a thousand cavalry to challenge Lun Kongre, shooting arrows with insult letter towards his camp. Lun Kongre became furious and led tens of thousands of troops in pursuit. After Pang Jiexin pretended to be defeated and retreated, appearing in a disheveled state, Lun Kongre intensified his pursuit. However, after advancing several tens of miles, the hidden ambush troops emerged, cutting off their retreat. Lun Kongre suffered a major defeat. At that moment, a violent storm occurred, causing the river to rise rapidly, and countless soldiers under Lun Kongre were swept away by the flood. The bodies stretched for fifty miles, while Lun Kongre himself managed to escape alone.

In the same year, the Gaochang Uighurs recaptured Yanqi and Kucha from Tubo dynasty.

In 844 AD, one of generals of Lun Kongre, the commander Jizang Fengtsan,chose to surrender to Zhang Bi Bi due to Lun Kongre's brutality.

In the same year, Lun Kongre organized his forces and attacked Shanzhou (now, Ledu, Qinghai) once again. Zhang Bi Bi divided his troops into five routes to intercept Lun Kongre, whom faced difficulties in advancing and retreated to Donggu. Zhang Bi Bi's army used wooden fences to surround Lun Kongre's forces and cut off their water supply. Unable to sustain the siege, Lun Kongre and more than a hundred of his soldiers broke through the encirclement and fled to Bohan Mountain, while the rest of the troops surrendered to Zhang Bi Bi.

In 845 AD, in the 12^th month of the lunar calendar, Lun Kongre gathered his remaining soldiers and attacked Zhang Bi Bi again. But they were defeated by Zhang Bi Bi's commander Pang Jiecang, who led five thousand troops. Lun Kongre and a few dozen cavalrymen managed to escape. Zhang Bi Bi sent out letters to spread the news in the area of the Hehuang (now, Yellow River and Huangshui basins in present-day Qinghai and Gansu provinces), recounting Lun Kongre's brutal crimes and urging the Tang people under Tibetan rule to return to Tang Dynasty and not be hunted down like foxes and rabbits by Lun Kongre and his army

In 846 AD, after Lang Damar was assassinated by the monk Lhalung Palkye Dorje , Langdama's two sons, Vosung and Yumtan, engaged in a war of succession for the position of the Tibetan Empire's ruler, known as the "Battle of Wuyue (Du-Yor Drugpa)"

Note: The "Battle of Wuyue (Du-Yor Drugpa)" is regarded as a turning point in the division and decline of the Tubo Empire. The influential border military commanders were also involved in the conflict, which lasted for over twenty years. During this war, Be Kotsan, the son of Vosong, died in a rebellion. Be Kotsan's son, Gyide Nymagun, realizing the situation was hopeless, then led his followers to escape to the Ali region. He married the daughter of a local tribe chief and established his own regime. After his death, his kingdom was divided into three parts: the eldest son, Ribagun, ruled the western region of Mayu (around Ladakh), the second son Drashi Degun ruled the southeastern part of Burang (present-day Pulan County), and the third son De Tsugun ruled Zhang zhung (present-day Zanda County), which later became known as the Guge kingdom.

In 847 AD, Lun Kongre, after suffering a setback in their westward expansion and failing to carry out their conspiracy, joined forces with the Tang Dynasty's enemy, the Partyans, and a portion of the Uighurs. They then launched attacks and plundered the Hexi Corridor of Tang dynasty, engaging in a battle with the Tang army led by Wang Zai, the military governor of Hedong, at Yanzhou (now,Dingbian County, Shaanxi province). As a result, Lun Kongre was defeated and forced to retreat.

In 848 AD, Tang army recaptured Qingshui County (now, administrated by Tianshui City, Gansu Province). That year, Lun Kongre once again sent their general, Mangluo Jicang, with an army of 20,000 to launch a westward campaign. However, the Tang general Tuoba Huaiguang intercepted them at Nangu Valley and inflicted a heavy defeat, causing Mangluo Jicang to surrender.

During the same year, the local people of Shazhou (now, Dunhuang, Gansu Province) in the former Hexi Northwest Circuit also rebelled against the Tibetan Empire. They seized Shazhou and Guazhou.(Guazhou County, Jiuquan City, Gansu Province)

In 849 AD, in the 1^st month of the lunar calendar, Tubo army stationed in Qinzhou, Yuanzhou, and Anle zhou, as well as Shimen, Yicang, Muxia, Zhisheng, Liupan, Shixia, and Xiaoguan surrendered to Tang army which soon took control of these regions.

In the 2^nd month of the lunar calendar, Lun Kongre stationed his troops in Hezhou (now Linxia Prefecture, Gansu Province), while Zhang Bi Bi stationed his army in Heyuanjun. Zhang Bi Bi's subordinates were eager for victory and prepared to attack Lun Kongre, but Zhang Bi Bi believed that his army had become complacent due to repeated victories, while Lun Kongre would fight desperately like trapped animals, indicating that the timing for an attack was not yet ripe. However, the other generals disagreed and insisted on going into battle. Zhang Bi Bi anticipated their inevitable defeat, so he led a portion of his forces to wait by the river bridge. As expected, Lun Kongre finally achieved a victory, and Zhang Bi Bi's subordinates returned in defeat. Zhang Bi Bi regrouped his soldiers, burned the river bridge, and retreated to Shanzhou (now, Ledu, Qinghai).

In 850 AD, Zhang Yichao captured Hami, Ganzhou, and Suzhou (now, Jiuquan city, Gansu provicne).

In the 9^th month of the lunar calendar, Lun Kongre dispatched Seng Mangluo Linzhen to lead troops to repair a bridge south of Jixiang Pass, in order to cross the river and attack Zhang Bi Bi. Zhang Bi Bi sent the general Zhang Duoluo Tatsang to ambush Lun Kongre's army in Linfan, but they were unsuccessful. They also sent Moli Pizi and "Drulu Gongli" to resist the enemy in Maoniu Gorge. At that time, Gongli suggested, "Hold our ground and refuse to fight. Use guerilla tactics to cut off their supply lines, so they cannot advance or retreat. Within a month or so, their forces will surely collapse." However, the main general, Moli Pizi, refused to adopt this strategy, and Gongli, unwilling to be a defeated general, used his illness as an excuse to return to Shanzhou. Moli Pizi insisted on his own course of action and went into battle, ultimately suffering a defeat.

Due to a lack of food in Shanzhou, Zhang Bi Bi led over 3,000 people to migrate west to Ganzhou, leaving Tuoba Huaiguang to guard Shanzhou. From then on, Zhang Bi Bi disappeared from historical records.

Because Zhang Bi Bi had repeatedly defeated Lun Kongre, their plot to expand westward and seize power became a mere illusion. The "New Book of Tang·Tibetan History" states that from then on, Lun Kongre rampantly attacked and plundered various provinces such as Buzhou, Kuozhou, Guazhou, and Suzhou, leaving a trail of death and destruction. Even his subordinates were disgusted by his brutal behavior.

In 851 AD, in the 1^st month of the lunar calendar, Zhang Yichao sent envoys to surrender to the Tang Dynasty. Tang Dynasty appointed Zhang Yichao as the Defense Commissioner of Shazhou. Afterward, Zhang Yichao rapidly expanded his influence, centered around Shazhou, and infiltrated neighboring regions, capturing Gaochang and Yutian.

In the 5^th month of the lunar calendar, Lun Kongre went to Tang Dynasty. Emperor Tang Xuanzong of Tang dynasty sent the Minister of Ceremonies, Lu Dan, to comfort them and ordered the armies from Jingyuan, Lingwu, Fengxiang, Binning, and Zhenwu to welcome Lun Kongre and his troops. Tang Dynasty attempted to make use of Lun Kongre, and the Deputy Minister of the Left, Li Jingrang, met with them. However, Lun Kongre behaved arrogantly. They wanted to be the military governor of He Wei Circuit. It was at this point that Tang Dynasty realized that Lun Kongre was not an ordinary person and not a submissive surrender. As a result, they lost interest in Lun Kongre and treated them as ordinary guests, sending them off in a friendly manner. Lun Kongre's plan once again failed.

When passing through the Weiyang Bridge, Lun Kongre sighed, saying, "I aimed to achieve great things, but I can only reach this river and divide the territory with Tang." They then returned to their base in Luomenchuan (now, Eastern Wushan County, Gansu Province), gathered their old troops, but soon faced continuous rainy weather and extreme food shortages. Many people dispersed, leaving only three hundred people who fled with Lun Kongre to Kuozhou (now, South of Guide county, Qinghai Province).

In the 10^th month of the lunar calendar, Zhang Yichao sent his brother, Zhang Yize, to the Tang Dynasty to present maps and household registers of eleven provinces, including Sha, Gua, Yi, Xi, Gan, Su, Lan, Shan, He, Min, and Kuo. The Tang Dynasty took this as a symbol of recovering the Hexi region. However, Zhang Yichao did not actually rule or occupy the mentioned eleven provinces because he had only recently occupied Shazhou, and it was impossible to conquer eleven provinces in just five months. At the same time, Tang Dynasty did not establish effective rule in this area.

In the 11^th month of the lunar calendar, Tang Dynasty established the Guiyi Army in Shazhou, with Zhang Yichao as the military governor and the observer of the eleven provinces. From then on, Zhang Yichao and his subordinates became one of the semi-independent powers in the northwest region of Tang dynasty

In the same year, Tuoba Huaiguang sent people to persuade the subordinates of Lun Kongre. Some of them fled from Lun Kongre and scattered among the tribes, while others surrendered to Tuoba Huaiguang. Lun Kongre became weak, and he planned to rely on Tang Dynasty. They intimidated their subordinates, saying that they would borrow 500,000 troops from Tang Dynasty to exterminate the rebels, and then make Wei Prefecture their capital, asking Tang Dynasty to confer the title of Tibetan king upon them. Amidst the chaos, some Tibetan generals also surrendered to Tang Dynasty.

In 857 AD, Tubo general "Zhang Yamsum" led approximately 10,000 tents from Hezhou, Weizhou, and the Wa tribe to surrender to Tang Dynasty. Li Chengxun, the military governor of Jingyuan, coveted the livestock of Zhang Yamsum's troops and deceived him into entering Fenglin Pass (located north of Fenglin County in Hezhou). Afterwards, relocated them to the west of Qinzhou. Subsequently, Li Chengxun and his generals planned to arrest Zhang Yamsum on charges of rebellion, then to plunder the wealth of the Tubo army and tribes, and then after relocate the Tubo people to the wilderness.

Upon learning of Li Chengxun's plot, Zhang Yamsum expressed his intentions at a banquet, saying, "Hezhou and Weizhou are sparsely populated. Due to famine and epidemic, many Tang people have been relocated to the Three Rivers region (Pingliang River, Yuruchuan, Luomen River), while the Tubo people have fled far west to Diezhou and Dangzhou, where there is no human presence for nearly two thousand miles. "Yamsum" desires to meet the Emperor and request to lead his troops to relocate to the interior, becoming the people of Tang Dynasty, so that there will be no more threats from the west. This achievement would be no less than that of Zhang Yichao." Li Chengxun and others were convinced by his words and abandoned their original plan. Afterwards, Tang Dynasty appointed Zhang Yamsum as the "Commander of Military Defense of Hezhou and Weizhou" and he was given authority over the Tubo people in this region.

In 862 AD, the weaker factions of the Tubo tribe (the Wa Mo group) were already independent and began paying tribute to Tang Dynasty, indicating that the Wa Mo group had established a relationship with Tang Dynasty. They were scattered between Gan,Su, Guazhou, Shazhou, Hexi, Weinan, Minxian, Kuozhou, Diezhou, and Dangzhou.

Some of the Wa Mo group surrendered to Tang Dynasty and were stationed along the southwestern Dadu River to defend against the Nanzhao Kingdom.

Note: Regarding "Wa Mo Tribe"

In 906 AD (Tang Dynasty, Tianyou Era), "In the spring, more than 7,000 Tubo cavalry camped at Zonggao Valley, preparing to attack Wa Mo and capture Liangzhou." Wa Mo had already separated from the Tubo tribe and become an independent group. During the Five Dynasties period (907-979 AD), Wa Mo was still active in the northwest region.

In 911 AD, "The Wa Mo leader Dulun Moxigai and Du Lunsum were appointed as Left Guard Generals. The Wa Mo Sulun Qilulun was appointed as Right Guard General

In 912 AD, the Wa Mo leader Rebu Bodu and Cuiyan Meixiang were appointed as Silver Blue Light Ministers. Later, Wa Mo tribe was assimilated by other tribes.

In 863 AD, Zhang Yichao led a force of 7,000 Tubo and Han soldiers to capture Liangzhou, indicating that there were Tubo soldiers among the forces of Tang dynasty

In 866 AD, Lun Kongre, who lived within the boundaries of Kuozhou, still harbored ambitions and prepared for a comeback. However, all Tubo tribes were disgusted by Lun Kongre's actions and refused to support him. Lun Kongre's enemies secretly reported the information to Zhang Bi Bi's subordinates, Tuoba Huaiguang, the leader of the troops stationed in Shanzhou.

In the 10^th month of the lunar calendar, Tuoba Huaiguang led 500 cavalrymen to Kuozhou and captured Lun Kongre whom was tortured and executed, then sent Lun Kongre's head to the Tang Dynasty as proof.

In 866 AD, Tubo Dynasty collapsed, leading to a state of chaos. Unified laws and institutions disappeared, the political structure gradually paralyzed, and the officials and military forces stationed in the border areas of Tubo were panicked. Some declared independence, while others surrendered to Tang Dynasty.

In the same year, the leader of the Uighur tribe, Pugu Jun, attacked Tubo's troops in the Western Regions. According to "New Book of Tang·Uighur Biography," it is recorded that "The great leader Pugu Jun attacked Tubo from Beiting, killed Lun Zhangre, and captured cities like Xizhou and Luntai." From then on, Tubo's influence in the Western Regions was primarily eliminated, and the oases in the desert became distant and unfamiliar places for the Tubo people. Tubo gradually lost control over the territories it had occupied through expansion in previous generations. This year is considered the year when Tubo's power retreated back to the Qinghai-Tibet Plateau.

In 869 AD, The "Battle of Wuyue (Du-Yor Drugpa)" that lasted for 23 years came to an end. Shortly after that, the Tubo Empire witnessed another uprising known as the "Slave Uprising (Great Rebellion of Subjects)." Although this Tubo slave uprising was of great magnitude, it occurred in a sequential manner. The first peasant uprising broke out in Do Kham, which seems to be related to the aforementioned Wa Mo uprising. The leader's name was Wei Ke Xi Lie Deng. Then, one by one, different regions of Tubo followed suit, starting with Ye Ru, followed by Wu Ru and Yue Ru, and rebellions sprouted up in various places. This period in history is referred to as "a bird rises high, and the rest fly together."

In the Yue Ru region, commoners could no longer bear the heavy labor of building canals in the mountains, so they took up arms and advocated the slogan, "It's easier to cut off heads than to cut off mountains." Later, under the leadership of uprising leaders like "Xu Boudai", the rebels marched towards the tombs of past Tubo rulers and destroyed most of the mausoleums. This was both a venting of their anger and an attempt to unearth buried treasures. The peaceful burial grounds turned into scenes of devastation, bearing witness to the decline of the Tubo Kingdom. The nobles and feudal lords, faced with the anger of the commoners and slaves, lost their former prestige, authority, and arrogance. Some were trampled by the rebel army, while others fled to different places. Even the son of Vosong, Be Kotsan, was killed by the rebels.

In 877 AD, the rebel army captured the Tubo capital city of Lhasa, allegedly plundered the royal tombs (although there are conflicting accounts), and systematically killed the royal family and nobles. The Tubo Dynasty collapsed completely, marking the end of over 200 years of unified rule. This marked the official beginning of a period of fragmentation and warlordism.

In 885 AD, Vosong died in the Podrang Pangthang Palace. After his death, he was buried in a mausoleum called Kyiu Lhaten. Since then, there has been no further construction of mausoleums. This information can be found in the handwritten manuscript "Yalong Jowo Buddhist History," page 43, and in "A Collection of Sino-Tibetan History," Volume I, page 149.

After the Tubo Dynasty

From the mid-ninth century to the early tenth century AD, the royal family in the entire Tubo region was divided, warlords and nobles fought fiercely, and slaves and commoners rebelled. The society was filled with warfare and violence, and all aspects of social production and culture suffered great destruction and loss. Everywhere was scarred and desolate.

It was not until the 11^th century AD that Tibetan society gradually became peaceful. The descendants of the Tubo royal family established multiple feudal separatist regimes, such as the Ladakh Dynasty in the Ali region, the Guge Dynasty, the Yalong Juea Dynasty in the central and southern parts of Tubo kingdom, and the Qingtang regime in the Gansu-Qinghai region. It was not until the 13^th century when the Yuan Dynasty unified the Qinghai-Tibet Plateau that the centuries-long period of division in Tibetan history came to an end.