Li Jiancheng
By 626, Li Jiancheng and Li Shimin were locked in an intense rivalry, and Li Shimin, fearing that Li Jiancheng might be intending to kill him, solicited advice from Li Shiji and another major general, Li Jing, and both refused to speak on the matter, drawing respect from Li Shimin for their unwillingness to be involved in an internecine struggle. In summer 626, Li Shimin ambushed Li Jiancheng and another brother, Li Yuanji the Prince of Qi, who supported Li Jiancheng, at Xuanwu Gate and killed them. He then effectively forced Emperor Gaozu to first create him crown prince and then yield the throne to him (as Emperor Taizong).