Tun Baga Tarkhan or Alp Qutlugh Bilge Qaghan — was the fourth leader of Uyghur Khaganate.
Luo Xin, historian at Peking University, proposed that he was in fact a younger brother of Yaoluoge Dunmohe.
Bögü's new plan on invading Tang dynasty due to pressure from Manichaean clergy caused him to establish his own anti-war faction.
If we mobilise our forces again and do not gain a victory, how will we return at all?Unable to accomplish his task, he murdered Bögü and his followers among him in 779/780, went on to declare himself a qaghan.
As an effort to obtain an alliance, Tun Baga sent an emissary to Tang China for a marriage proposal on 2 October 787.
Emperor Dezong hated the Uyghurs, ever since several of his attendants were tortured and killed by Bögü Qaghan in 762 while he was still a prince and therefore refused.
'Long living', 'Heaven blessed Qaghan') along with the princess who was created Zhihuiduan Zhengshou Xiaoshun Khatun (Chinese: 智慧断征收孝顺可敦; lit.
According to Luo Xin, he as posthumously renamed Bögü Bilge Tengri Qaghan (Old Turkic: 𐰋𐰇𐰏𐰇:𐰋𐰃𐰠𐰏𐰀:𐱅𐰭𐰼𐰃:𐰴𐰍𐰣).