Incident at Xuanwu Gate

The Incident at Xuanwu Gate (玄武門之變) refers to an incident on July 2, 626 [The date of the incident at Xuanwu Gate was the fourth day of the sixth month of the "Wude" era, which translates to July 2, 626, according to the Academia Sinica. [http://www.sinica.edu.tw/ftms-bin/kiwi1/luso.sh?lstype=2&dyna=%AD%F0&king=%B0%AA%AF%AA&reign=%AAZ%BCw&all=1&yy=&ycanzi=&mm=&dd=&dcanzi=] .] , when Li Shimin the Prince of Qin, a son of Emperor Gaozu of Tang (the founding emperor of the Chinese dynasty Tang Dynasty), in an intense rivalry with his older brother Li Jiancheng the Crown Prince and fearing that Li Jiancheng was about to kill him, set an ambush at Xuanwu Gate, the gate leading to Emperor Gaozu's palace, and killed Li Jiancheng and a younger brother, Li Yuanji the Prince of Qi, who had supported Li Jiancheng. He then sent forces into Emperor Gaozu's palace. Emperor Gaozu, under intimidation, created him crown prince, and two months later passed the throne to him (as Emperor Taizong).

Events leading up to the incident

Emperor Gaozu and his wife, Duchess Dou (who had died prior to his founding of the Tang Dynasty and becoming emperor in 618 and whom he had posthumously honored as an empress) had four sons, Li Jiancheng, Li Shimin, Li Xuanba (李玄霸, who died in 614), and Li Yuanji. After the founding of the Tang Dynasty, Li Jiancheng, as the oldest son, was created crown prince, but while he was a capable general himself, he was overshadowed by Li Shimin, who had been the one who persuaded Emperor Gaozu to rebel against Emperor Yang of Sui in the first place, and who had defeated four of Tang's most powerful competitors -- Xue Rengao the Emperor of Qin, Liu Wuzhou the Dingyang Khan, Dou Jiande the Prince of Xia, and Wang Shichong the Emperor of Zheng. Emperor Gaozu gave these three sons plenary powers, and within the Tang capital Chang'an, it was said that the orders of the Crown Prince, the Prince of Qin (Li Shimin), and the Prince of Qi (Li Yuanji) carried equal weight as the emperor's edicts. Traditional histories indicated that because of Li Shimin's contributions, at various times, Emperor Gaozu considered replacing Li Jiancheng with him, but eventually did not, as Li Jiancheng was supported by Li Yuanji and Emperor Gaozu's favorite concubines.

As the years passed, the rivalry between the brothers intensified, and their respective staff members advised each of them to act first against the other. At one point, when Li Shimin visited Li Yuanji's mansion, Li Yuanji wanted to assassinate him, but Li Jiancheng, not willing to do so, stopped the assassination. Nevertheless, Li Jiancheng feared Li Shimin, and in 624, against Emperor Gaozu's regulations, he tried to supplement his guards with soldiers under the command of the general Li Yi the Prince of Yan. When this was discovered, Emperor Gaozu angrily put Li Jiancheng under house arrest. Li Jiancheng's guard commander Yang Wen'gan (楊文幹), fearing that he would be punished, rebelled, and in light of Yang's rebellion, Emperor Gaozu offered Li Shimin the crown prince position and ordered him to attack Yang, who soon was killed by his subordinates. While Li Shimin was away battling with Yang, however, Li Yuanji, Feng Deyi, and Emperor Gaozu's concubines interceded on Li Jiancheng's behalf, and Emperor Gaozu allowed Li Jiancheng to remain crown prince, while exiling his staff members Wang Gui and Wei Ting (韋挺), and Li Shimin's staff member Du Yan.

Li Shimin, meanwhile, was trying to persuade Emperor Gaozu to allow him to leave Chang'an and become in charge of Luoyang, the former eastern capital of Sui Dynasty. At one point, Emperor Gaozu agreed, but Li Jiancheng and Li Yuanji, fearing that Li Shimin would use Luoyang as a power base to eventually act against them, spoke against the plan, and the plan was not carried out. They further falsely accused Li Shimin of crimes, but because of intercession by the official Chen Shuda (a brother of Chen Dynasty's last emperor Chen Shubao), Li Shimin was not punished. Nevertheless, wanting to reduce Li Shimin's power, Li Jiancheng and Li Yuanji had Li Shimin's staff army officers Yuchi Jingde and Cheng Zhijie (程知節) removed from Li Shimin's staff, as well as his strategists Fang Xuanling and Du Ruhui.

Li Shimin's killing of Li Jiancheng and Li Yuanji

In summer 626, the Eastern Tujue general Ashina Yushe (阿史那郁設) had entered Tang territory and put Wucheng (烏城, in modern Yulin, Shaanxi) under siege. Usually, Li Shimin would be sent against Eastern Tujue forces, but at Li Jiancheng's recommendation, Emperor Gaozu commissioned Li Yuanji to do so, and the troops under Li Shimin were transferred to Li Yuanji. Li Shimin, fearful that Li Jiancheng and Li Yuanji would use this opportunity to act against him, decided to act, particularly at the urging of his brother-in-law Zhangsun Wuji and Yuchi Jingde. He had Fang Xuanling and Du Ruhui secretly recalled to his mansion to draw the plans for action, and then one night submitted a secret accusation to Emperor Gaozu, accusing Li Jiancheng and Li Yuanji of affairs with Emperor Gaozu's concubines and plans to kill him. Emperor Gaozu was surprised by the accusation and promised to handle Li Shimin's accusation the next day, and summoned the high level officers Pei Ji, Xiao Yu, and Chen Shuda to prepare to act on the accusations.

The next morning, Li Shimin and Zhangsun Wuji first went to Emperor Gaozu's palace, and secretly took over the command at Xuanwu Gate -- the north gate of the palace. Meanwhile, Emperor Gaozu's concubine Consort Zhang had heard what Li Shimin had accused Li Jiancheng and Li Yuanji of, and secretly informed them. Li Yuanji advocated not reporting to the palace, but instead preparing troops for battle, but Li Jiancheng, while mobilizing the troops, wanted to go see Emperor Gaozu to see what the situation is, and so they proceeded toward the palace.

When Li Jiancheng and Li Yuanji reached the palace, they began to sense that something was wrong, and they, on their horses, began to head back to Li Jiancheng's palace. Li Shimin personally chased them and yelled out, "Big brother!" Li Yuanji fired three arrows at Li Shimin, missing each time. Li Shimin fired an arrow at Li Jiancheng, killing him. Yuchi Jingde then arrived with 70 soldiers, and Li Yuanji fell off his horse. Li Shimin's horse was spooked and took him into a forest. Li Shimin fell off the horse and could not get up. Li Yuanji then entered the forest and tried to strangle Li Shimin with his bow, but at this point Yuchi arrived, and Li Yuanji tried to flee. Yuchi chased him down and killed him with an arrow.

Aftermaths

Meanwhile, Li Jiancheng's guard commander Feng Li (馮立), although he heard that Li Jiancheng had died, felt that to be faithful to Li Jiancheng, he should mobilize for battle anyway, and therefore he, along with the other officers Xue Wanche (薛萬徹) and Xie Shufang (謝叔方), commanded Li Jiancheng's and Li Yuanji's guards and headed for Xuanwu Gate, where they encountered Li Shimin's guards. Initially, they prevailed, killing Li Shimin's guard commanders Jing Junhong (敬君弘) and Lü Shiheng (呂世衡), but Yuchi Jingde then arrived and displayed the heads of Li Jiancheng and Li Yuanji. Li Jiancheng and Li Yuanji's guard corps collapsed upon seeing their heads, and Feng and Xue fled.

Meanwhile, Li Shimin sent Yuchi into the palace with guards, and Yuchi advanced all the way into Emperor Gaozu's presence. Emperor Gaozu was shocked and asked what Yuchi was doing there, and Yuchi responded:

Emperor Gaozu, realizing how serious the situation was, asked Pei Ji, Xiao Yu, and Chen Shuda for advice, and Xiao and Chen advised him to create Li Shimin crown prince to placate him. At Yuchi's request, Emperor Gaozu issued an edict ordering the remaining Crown Prince and Qi troops to stop their resistance and submit to Li Shimin. He summoned Li Shimin, whom he comforted with kind words, and Li Shimin knelt and cried. Li Shimin nevertheless had Li Jiancheng's and Li Yuanji's sons executed, while having Emperor Gaozu issuing an order pardoning Li Jiancheng's and Li Yuanji's staff members. Three days later, Emperor Gaozu created Li Shimin crown prince and ordered that all matters be submitted to Li Shimin for ruling. Two months later, he passed the throne to Li Shimin, who took the throne as Emperor Taizong.

References

* "Zizhi Tongjian", vol. 192.
* "Book of Tang", vols. 2, 64 [http://ef.cdpa.nsysu.edu.tw/ccw/02/tan08.htm] .
* "New Book of Tang", vols. 2, 79 [http://ef.cdpa.nsysu.edu.tw/ccw/02/ntan13.htm] .