Li Jiancheng
By 626, Li Shimin was fearful that he would be killed by Li Jiancheng, and his staff members Fang Xuanling, Du Ruhui, and Zhangsun Wuji were repeatedly encouraging Li Shimin to attack Li Jiancheng and Li Yuanji first—while Wei Zheng was encouraging Li Jiancheng to attack Li Shimin first. Li Jiancheng persuaded Emperor Gaozu to remove Fang and Du, as well as Li Shimin's trusted guard generals Yuchi Jingde and Cheng Zhijie, from Li Shimin's staff. Zhangsun Wuji, who remained on Li Shimin's staff, continued to try to persuade Li Shimin to attack first.