당 고종
In 657 Emperor Gaozong of Tang started the Conquest of the Western Turks. General Su Dingfang was appointed to be leading commander during whole operation. Chumukun tribe was first to lose whose chief Lantulu (懶獨祿) submitted. Tang army defeated Ishbara at the Battle of Irtysh River. However he fled to Chach with his son Ashina Xiyun and a noble retainer Xuyan. However he was soon handed over to Xiao Siya (萧嗣业) by Chach ruler Yixian Tarkhan.