Li Chengqian
Li Tai, who carried the title of Prince of Wei, was favored by his father, Emperor Taizong, for his literary talent and studiousness. His older brother Li Chengqian was crown prince, but Li Tai and his associates had design on that position, eventually pushing Li Chengqian to plot treason in 643. After Li Chengqian's plot was discovered, Li Chengqian was deposed, and Emperor Taizong agreed to create Li Tai the new crown prince. However, Emperor Taizong soon saw that Li Tai had pushed Li Chengqian toward rebellion by machination and further appeared to bear ill intentions toward their younger brother Li Zhi the Prince of Jin, and so Emperor Taizong created Li Zhi crown prince instead. Li Tai was reduced in rank and briefly put under house arrest, and then exiled. He died in exile in 653.