…the officers Erzhu Huan and Qiao Gongshan inform Emperor Gaozu that Li Jiancheng is encouraging Yang to start a rebellion so that they could seize power together.
Emperor Gaozu, then at Renzhi Palace (in modern Tongchuan, Shaanxi), is incensed, and summons Li Jiancheng from Chang'an to Renzhi Palace.
Li Jiancheng briefly entertains the notion of occupying Chang'an and not accepting the order, but eventually reports to Renzhi Palace to request forgiveness.
Emperor Gaozu puts him under arrest.
When Yang hears this, Yang rebels, and Emperor Gaozu, after promising Li Shimin that he would be made crown prince, sends Li Shimin to attack Yang.
(Under Emperor Gaozu's promise, Li Jiancheng will be removed as crown prince and created the Prince of Shu instead.
He will then send Li Jiancheng to the modern Sichuan region.)
Once Li Shimin leaves, however, Li Yuanji, Emperor Gaozu's concubines, and the chancellor Feng Deyi, all speak on Li Jiancheng's behalf, and Emperor Gaozu changes his mind, releases Li Jiancheng, and allows him to return to Chang'an and remain as crown prince.
Instead, Emperor Gaozu only blames the discord between his sons on Li Jiancheng's staff members Wang Gui and Wei Ting, and Li Shimin's staff member Du Yan, exiling them.
Yang is subsequently assassinated by his own subordinates.
