侯君集
Meanwhile, Qu Wentai (), the king of Gaochang, was said to have allied himself with Western Tujue against Tang, and also tried to engage Xueyantuo in their alliance, sending an emissary to Yi'nan to tell him, "You are a khan, and you have enough power to stand up to the emperor. Why bow to his emissary?" Yi'nan, in response, informed Emperor Taizong of Qu's instigation and, when Emperor Taizong sent the general Hou Junji to attack Gaochang in 638, offered to send an army to assist Hou. Emperor Taizong sent the official Tang Jian and the general Zhishi Sili () to Xueyantuo, to award Yi'nan with silk for his loyalty and to discuss coordination. (However, when Hou actually attacked and conquered Gaochang in 639, it appeared to be without actual participation from Xueyantuo.)