Li Shimin was wise and courageous, and made great contributions to the Tang Dynasty, and the crown prince Li Jiancheng, fearing that his position as crown prince would be replaced by Li Shimin, joined forces with Li Yuanji to repeatedly try to get rid of Li Shimin, forcing Li Shimin to launch the "Xuanwumen Revolution".
Li Shimin first complained to Li Yuan that Li Jiancheng and Li Yuanji were in turmoil in the harem, and Li Yuan decided to summon Li Jiancheng and Li Yuanji to the palace for interrogation, and Li Shimin and Wei Chigong and others led people to ambush at the Xuanwu Gate, the north gate of the palace, which was the only way for Li Jiancheng to enter the palace. Originally, Chang He, the commander-in-chief of the Xuanwu Gate Control Army, was the crown prince, but was later bribed by Li Shimin.
When Li Jiancheng passed through the Xuanwu Gate, he did not see Chang He, the guards were all unfamiliar faces, he felt the danger, and then he and Li Yuanji turned the horse's head and ran, at this time Li Shimin led the ambush troops to rush out, Li Yuanji saw that the situation was not good, he took a bow and shot an arrow, because of his panic, he did not even shoot three arrows to hit Li Shimin, and Li Shimin wanted to kill Li Jiancheng, who was about to flee, with one arrow.
Li Yuanji was hit by an arrow in the fierce battle, fell off his horse, and was just hacked to death by Wei Chigong, who arrived in time with a sword. Wei Chigong then cut off li jiancheng and Li Yuanji's heads and scared off the generals of the prince's mansion who came to support.
In the end, Li Yuan was forced to pass the throne to Li Shimin and became emperor himself.
So Li Shimin shot Li Jiancheng, and Wei Chigong hacked Li Yuanji to death!
![Li Jiancheng poisoned Li Shimin, and Li Shimin vomited several liters of blood and did not die, not because of the mercy of his eldest brother[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)