Yang Liang
Meanwhile, Emperor Wen much favored Yang Liang, but Yang Liang was becoming ambitious and troubled by the removal of his oldest brother, Yang Yong, as crown prince in 600. (Yang Guang replaced Yang Yong as crown prince.) He therefore persuaded Emperor Wen that his headquarters at Taiyuan was the key to the defense against Tujue, so Emperor Wen permitted him to produce weapons and build up Taiyuan's defenses. Two of his trusted generals, Wang Kui () and Xiao Mohe, both of whom believed that they should have been given greater responsibility by Emperor Wen, also encouraged him to eventually consider rebelling. Yang Liang was further troubled after another brother, Yang Xiu the Prince of Shu, was deposed over charges of wastefulness in 602. (Part of the charges against Yang Xiu, which appeared to have been manufactured by Yang Guang, was that Yang Xiu secretly cursed Emperor Wen and Yang Liang, but there was no evidence indicating that Yang Xiu actually did so or that Yang Liang believed Yang Xiu did or resented Yang Xiu over it.)