Bögü Qaghan

He was viceroy of eastern part of the khaganate during his father Bayanchur's reign. Bögü succeeded him in 759. He was approached by Shi Chaoyi, who offered him to march on Tang together. This proposal alarmed the khagan who rode 100.000 Uyghur soldiers to Tang border, believing the dynasty was fallen. However, Emperor Daizong sent an embassy in 762, reminding his friendship with late brother of qaghan, asking for alliance.[5] Li Kuo - supreme commander of Tang forces met with qaghan on 12 November 762 in his camp near Hebei and agreed to attack remaining rebel forces. However a number of his staff members had been arrested and killed over a dispute in the meeting protocol between the young prince and the khan. This started a hatred in Li Kuo against Uyghurs. for rest of his life. In any case, Shi Chaoyi was crushed by combined forces of Bögü and his father-in-law Pugu Huai'en near Luoyang and fled. Bögü returned to the steppe on 8 April 763 via Taiyuan. This successful war greatly improved Uyghur influence, all Uyghur officials together received a total tax income of 20,000 households, there were even reports about Uyghur soldiers arbitrarily capturing civilians in Changan markets to sell them as slaves in middle of day[5]. Even they were arrested, Daizong set them free.[6]

Bögü allowed a contingent of Uyghurs to join forces with Tang China against invading Tibetan forces in 765-768. Some these commanders included his younger brother and ministers Motu Baga Tarkan, Tun Baga Tarkhan, Kutlug Bilge, Jiela Boyla Tarkhan, Prince Ulu Tarkhan, Haiying Kül Tarkhan.[5]

The remaining Uyghur generals An Ke (安恪) and Shi Diting (石帝庭) gathered groups of bandits and pillaged the region. Despite the treaty, Uyghurs kept raiding Chinese territories. They invaded Taiyuan on 22 February 778, injuring and killing almost 10000 Tang soldiers.

Bögü met 4 Manichaean priests, including one certain Ruixi (睿息)[7] in Luoyang was interested in their religion. He took them to Ordu-Baliq and converted to Manichaeism and declared it a state religion in 763. Using his influence, he posed as the protector of Manicheans and asked Daizong to re-open Manichaean temples in the empire in 768. The emperor did not sympathize with the Manichaeans, but was forced to give permission in 771. His Manichean followers urged him to invade Tang China, following Daizong's death in 779. This prompted a coup-de-etat inside court led by Chief Minister Tun Baga Tarkhan, who was a zealous Tengriist and did not want any new war with Tang. Bögü was murdered along with 2000-3000 his supporters and relatives in 780.

Bögü khagan was married to Pugu Huaien's daughter Quangin Khatun (光亲可敦). She died in 768. Emperor Daizong created another daughter of Pugu Huai'en as Princess Conghui (崇徽公主) on 2 June 769 and sent her as continuing the heqin treaty. She was given 20.000 pieces of silk as dowry.

According to Larry Clark, as the first ruler in history to adopt Manichaeism as personal and state religion, Bögü Qaghan was strongly revered by later Manichaean traditions.[7]