Hou Junji
In 640, after a number of years during which Qu Wentai, initially submissive to Tang, became hostile to Tang interests and had allied himself with Western Tujue, Emperor Taizong sent Hou Junji to conquer Gaochang. Qu Wentai died from illness during the siege, and his son Qu Zhisheng () surrendered. Wei advised that Emperor Taizong should keep Qu on the throne, as an ally—a suggestion that Chu Suiliang also spoke of—but Emperor Taizong disagreed and annexed Gaochang directly. (Emperor Taizong would later regret this in 642, when the need to station soldiers at Gaochang became more and more expensive in monetary and human costs.) When Hou's lieutenant Xue Wanjun () was subsequently accused of raping Gaochang women, Emperor Taizong was going to hold cross-examination sessions between Xue and the alleged victims, but on Wei's urging—that whatever the results were, the empire would be harmed—Emperor Taizong cancelled the investigation.