Li Tai
in 643, Li Chengqian, apprehensive that he might be replaced by Li Tai, conspired with Hou, his brothers-in-law Zhao Jie (趙節) and Du He (杜荷), and his uncle Li Yuanchang (李元昌), the Prince of Han, to overthrow Emperor Taizong. The plot was discovered, and Emperor Taizong deposed Li Chengqian while executing the other conspirators. He then promised Li Tai he would be created crown prince—and Li Tai, wanting to appear appreciative, told Emperor Taizong that, if he were allowed to inherit the throne, he would kill his own son and make his younger brother, Li Zhi (the Prince of Jin), crown prince. Emperor Taizong was touched, but Chu immediately pointed out the disingenuity in Li Tai's remarks, and advocated that Li Zhi be made crown prince instead—an opinion shared by Emperor Taizong's brother-in-law Zhangsun Wuji, who was a maternal uncle of both Li Tai and Li Zhi. Soon, Emperor Taizong, who had also come to the conclusion that Li Tai's machinations were responsible for Li Chengqian's downfall, after first revealing his decision only to Zhangsun, Chu, Fang Xuanling, and Li Shiji, created Li Zhi crown prince and exiled Li Tai. Chu was made a junior advisor to the new crown prince, and Emperor Taizong had him, Liu Ji, Cen Wenben, and Ma Zhou often visit Li Zhi to advise Li Zhi on his studies.