young to rule the kingdom, Empress Dowager Xiao became the regent. Emperor Taizong decided to launch the second campaign against Liao in 986, following the advice of his subjects. During this time, Zhao Yuanzuo, Taizong's oldest son became insane after the death of his uncle, Zhao Tingmei, and that he was not invited to the Double Night Daylight Feast which ultimately caused Yuanzuo to burn down the palace. As a result, Taizong, under the pressure of his censors demoted Yuanzuo to commoner status and exiled him. This, was changed when 100 officials rejected Yuanzuo's exile and pressured Taizong to let Yuanzuo remain in the palace. Three officials who had responsibility for Yuanzuo asked to be punished by Taizong in which Taizong said "This son, even I have been unable to reform through my teaching. How could you guide him?" in response. In 983, the practice of officials tutoring imperial princes began under his reign. One notable case was Emperor Taizong's son Zhao Yuanjie and his tutor Yao Tan (935–1003) in which Yao constantly berated the young prince for being idle and lazy causing resentment from the prince. Yao attempted to complain to Taizong who said "Yuanjie is literate and enjoys learning; that should be sufficient to make him a worthy prince. If when young he is immoderate, then it is necessary to have entreaties to rein in his ridicule. But if you slander him without good reason, how is that going to help him?" However, Yuanjie under peer pressure from his friends feigned illness and began neglecting his duties. Concerned, Taizong checked the Prince's progress daily. He summoned Yuanjie's wet nurse after the Prince still was "ill" for a month with the wet nurse stating "The Prince is basically not sick; it's just that with Yao Tan checking up on him, he can seldom follow his inclinations, and thus has become sick." This enraged Emperor Taizong ordering her to be caned. Emperor Taizong remained in Bianjing and directed the war there without personally entering the battlefield. He split the army into three sections – East, Central and West. The East Army was led by Cao Bin, the Central Army by Tian Zhongjin and the West Army by Pan Mei and Yang Ye. All the three armies would attack Yanjing from three sides and capture it. The campaign was termed as the Yongxi Northern Campaign as it took place in the