The Sino-Tibetan Treaties in the Tang Dynasty
The Sino-Tibetan treaties were the conclusions of seven “sworn covenants” between 706 and 822 between China and Tibet in the Tang Dynasty. Throughout all of the Chinese dynasties – Qin to Qing – the Chinese entered into many treaties with non-Chinese states. However, there were none that had as many sworn covenants as with the Tibetans.
Before this, the Xiongnu and Han (206 BCE – 220 CE) had concluded peace treaties but there was only one official treaty that had been drawn up in 43 BCE between them; “the Khitan- Liao (947-1125) concluded two sworn treaties with the Northern Song (960-1127), and the Jurchen-Jin (1115-1234) five with the Northern and the Southern Song (1127-1279) governments, respectively”.
Tibet, also known as Tufan to the Chinese, rose as a united and commanding kingdom under the Yarlung dynasty around the end of the sixth century and the beginning of the seventh. Previously, they had been fragmented under the leadership of several chieftains, the most powerful being the kingdom/state of Tuyuhun in modern day Qinghai Province. Before the sixth century, there seems to be no evidence of any powerful political organization before Tufan.
Srong btsan sgam-po was the king of Tufan and, under his leadership, became a force to be reckoned with. This in itself is an interesting debate amongst scholars – while the nomads around China had became a constant problem for China, rising and falling for centuries, the rise of a powerful Tibetan kingdom was a one-time success. However, it caused significant problems for the Tang Dynasty, who had came to power around the same time as Srong btsan sgam-po.
The first problem came when Srong btsan sgam-po proposed marriage between himself and a Tang princess in 634 CE. Emperor Taizong refused but the Tibetan envoy told his king that the Tang emperor had first agreed but then changed his mind after the Tuyuhun qaghan arrived at the Tang court and fomented discord. “The change of Tang attitude was determined by Taizong’s consideration for relations with the Tuyuhun. In 634 when Tang and the Tuyuhun were at war, Taizong would have welcomed an alliance with Tibet so as to check the Tuyuhun from the rear. However, from 634 to 636 the situation in the Tuyuhun kingdom had changed drastically with the establishment of a pro-Tang regime, and the necessity to ally with Tibet against the Tuyuhun therefore disappeared. The Tibetan btsan-po [the king]decided to launch an attack against the Tuyuhun. It was only after Tibet had shown its insistence and military strength by attacking the Tuyuhun and the Tang frontier, that Taizong agreed to its request for marriage”.
The beautiful princess Wencheng was sent to Tibet and this led to a short peace between the two kingdoms. However, the Tibetans caused problems for the Chinese – they tried to expand their territory, and then detained the Tang envoy Chen Xingyan for ten years before his death after he refused to kowtow at the Tibetan king. “In 670 following their victory over the Chinese in battles at the Dafeichuan near Qinghai (Koko Nor), the Tibetans occupied all the territory of the Tuyuhun. In 678, 180,000 Tang troops were defeated in the battle with the Tibetans at Koko Nor. Tibetan expansion reached its peak.War and peace alternated between the two states and towards the end of the emperor Xuanzong’s reign Tang seemed to have the upper hand … In 763 they even occupied the Tang capital Chang’an for fifteen days and established temporarily a puppet Chinese emperor, a Tang prince whose sister Princess Jincheng had married a Tibetan btsan-po around 707”.
The Tibetan kingdom caused many problems for the Chinese and so treaties were enforced. The first was in 706 when Tibet was weakened. We do not have all the correct information but it appears that the treaty was “the demarcation of the boundary between the two states”.
The Second treaty was concluded in 732 when both sides had been weakened due to wars. We have no records regarding the ceremony but we do have information on the negotiations – they “started in 730 when Tibet delivered a letter on the Tang border, suggesting a peace agreement. Xuanzong at first wanted to refuse the request on the grounds of Tibet’s previous use of arrogant language and insistence on equal status. He was later persuaded to agree to the peace request and envoys were despatched to Tibet”.
The Third Treaty was in 762 after the An Lushan Rebellion. A new Tibetan king was enthroned and 756 and 757 the btsan-po volunteered to provide assistance to Tang in suppressing the rebels and asked to contract a marriage.
The Fourth treaty was in 765. “Like the previous one, this treaty was not effective in guaran-teeing peace. Tibet soon joined the rebellious Tang general Pugu Huaien together with the Uighurs in the ninth month of 765 in a formidable expedition aimed at Chang’an. Fortunately for the Chinese, Pugu died of a sudden illness on the way, which provided an opportunity for the Chinese to persuade the Uighurs into an alliance against the Tibetans. The critical situation was relieved”.
The Fifth treaty was in 767, the third time that a ceremony was held between both sides, but failed to keep the peace.
The Sixth treaty was in 783 when the emperor Dezong who, “instead of just passively defending the borders he took the initiative to make peace with Tibet by sending Wei Lun as an envoy, by ordering the frontier troops not to make provocative attacks on Tibet, and by returning eight groups of Tibetan envoys who had come to Tang during Daizong’s time and had been detained by the court due to the constant hostilities and wars between the two sides. Similarly, more than 500 Tibetans captives who had been settled in the south of China were returned”.
The Seventh Treaty was in 821/822. Both sides were exhausted and wanted to end the hostilities. In the ninth month of 821 Muzong agreed to the request from Tibet to conclude a peace treaty. In it, both sides declared that both countries were equal.
“Even after the treaty was concluded, border conflicts still occur-red in 821 and 822. Peace, however, prevailed most of the time from 822 to 847, only interrupted by a Tibetan incursion in 830 and by the incident of Weizhou (in modern Sichuan) in 831, when the Chinese first accepted the submission of Xi-da-mou, the Tibetan Vice Commissioner of Weizhou, and his people, but then returned them to Tibet. Xi-da-mou and his followers were executed by the Tibetan court. During this period diplomatic communications continued, with Tibet sending at least fifteen missions to Tang and Tang ten to Tibet”.
Pan, Yihong (1992) The Sino-Tibetan Treaties in the Tang Dynasty, T’oung Pao, BRILL.