Bögü Qaghan
Bögü Qaghan or Tengri Qaghan was the third qaghan of the Uyghurs. He was the younger son of Bayanchur Qaghan. His personal name was Yaoluoge Yidijian and was titled Ulu Bilge Töles Shad during his father's reign. His subsequent regnal names upon inheriting the throne were Tarkhan Bögü Qaghan, Alp Külüg Bögü Qaghan, and finally Tengrida Qut Bolmish El Tutmish Alp Külüg Bilge Qaghan. He was posthumously named Kün Tengrida Qut Bolmish El Tutmish Alp Külüg Bilge Qaghan by Baoyi Qaghan, stressing his adoption of the Manichean religion. Other titles granted to him were Yingyi Qaghan, a Tang dynasty invested title and Zahag-i Mani, a Manichaean title.
He is known for being the most powerful monarch of the Uyghur Khaganate, converting to Manichaeism in 763, and founding the Por-Bazhyn Palace.
Reign
Bögü Qaghan was viceroy of eastern part of the Uyghur Khaganate during his father Bayanchur's reign. Bögü succeeded him in 759. He was approached by Shi Chaoyi, who asked him to march on Tang with him. This proposal alarmed the Qaghan who rode 100,000 Uyghur soldiers to the Tang border, believing the dynasty had fallen. However, Emperor Daizong sent an embassy in 762, reminding him of his friendship with Bögü's late father, asking for an alliance. Li Kuo, supreme commander of Tang forces met with Bögü on 12 November 762 in his camp near Hebei and agreed to attack the 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 Bögü. This started a hatred in Li Kuo against Uyghurs for the rest of his life. In any case, Shi Chaoyi was crushed by the 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 Chang'an markets to sell them as slaves in the middle of the day. Even when they were arrested, Daizong set them free.Bögü allowed a contingent of Uyghurs to join forces with Tang China against the invading Tibetan forces from 765 to 768. Some of these commanders included his younger brother and ministers Motu Baga Tarkan, Tun Baga Tarkhan, Kutlug Bilge, Jiela Boyla Tarkhan, Prince Ulu Tarkhan, and Haiying Kül Tarkhan.
The remaining Uyghur generals An Ke and Shi Diting gathered groups of bandits and pillaged the region. Despite the treaty, the Uyghurs kept raiding Chinese territories. They invaded Taiyuan on 22 February 778, injuring and killing almost 10,000 Tang soldiers.