su dingfang's forces comprised tang soldiers and 10,000 uyghur horsemen. the uyghur troops were provided by porun, son of the uyghur leader tumidu eltabar and enthroned by taizong. the uyghurs were allied with tang china, who had supported their revolt against the reign of the xueyantuo, a tribe of tiele people. porun joined su dingfang as a vice commander of the uyghur cavalry in the military campaign against the western turks. the commanders of the uyghur cavalry were the yanran protector-general and vice protector-general, administrators of the yanran protectorate near the tang xishouxiang military garrison.