刘武周
Emperor Yang grew dissatisfied with Li Yuan and Wang Rengong (), the governor of Mayi Commandery (, roughly modern Shuozhou, Shanxi), over their inability to stop incursions by the Eastern Turks (Tujue) and the growing strength of agrarian rebels—particularly the Turk-supported Liu Wuzhou, the Dingyang Khan, who soon rose against Wang and killed him and captured Emperor Yang's secondary palace near Taiyuan. Li Yuan also became fearful due to prophecies circulating throughout the empire that the next emperor would be named Li—and because Emperor Yang had killed another official, Li Hun () and his clan over his fears that Li Hun's nephew Li Min (, the son-in-law of Emperor Yang's sister Yang Lihua, the Princess Leping) had imperial ambitions.