Xuanwu Gate Incident

After the Tang dynasty was founded, Emperor Gaozu, Li Yuan, made his eldest son Li Jiancheng crown prince, his second son Li Shimin Prince of Qin, and his fourth son Li Yuanji Prince of Qi. In the wars to unify the country, Li Shimin defeated rival warlords including Xue Ju, Liu Wuzhou, Wang Shichong and Dou Jiande. His great merit earned him the title “Celestial Strategist General”, placing him above the other princes, and his household gathered many talents. Crown Prince Li Jiancheng also had achievements, such as putting down Liu Heita, but lacked Li Shimin’s prestige. He allied with Li Yuanji to push the Prince of Qin aside, and the rivalry grew sharper. In 626 the Turks invaded, and Li Jiancheng proposed that Li Yuanji lead the army, hoping to draw off the elite troops and officers of Li Shimin’s household. Li Shimin struck first. On 2 July 626, at dawn, he set an ambush at Xuanwu Gate, the north gate of the Taiji Palace in Chang'an, with Zhangsun Wuji, Yuchi Jingde and others. As Li Jiancheng and Li Yuanji came to court, Li Shimin shot Li Jiancheng himself and Yuchi Jingde killed Li Yuanji; their sons were killed as well. Li Yuan was then forced to name Li Shimin crown prince and hand state and military affairs to him. In the eighth lunar month Li Yuan abdicated as retired emperor and Li Shimin took the throne, adopting the era name Zhenguan the following year. He is Emperor Taizong of Tang. The incident was a brutal palace coup over the succession, but after taking power Li Shimin ruled diligently, accepted criticism and employed capable ministers, inaugurating the “Rule of Zhenguan”. Most accounts of the incident in the histories come from records made during Taizong’s reign, and later generations have differed over its details.