After the change of Xuanwu Gate, Li Shimin visited Li Yuan, Li Yuan: What about the King of Qi and the Crown Prince? Li Shimin: Killed
When it comes to Li Shimin, I think everyone will think of the Xuanwumen Change, that is, in this coup d'état, Li Shimin took the position of emperor. After this incident, when Li Yuan asked Where Prince Li Shimin and King Qi were, he did not expect that the answer was that he had been killed.
On July 2, 626 A.D., Li Shimin entered the dynasty with his cronies, and they had already buried their swords and axes next to the Xuanwu Gate. At that time, the prince and the king of Qi did not feel anything unusual, until they reached the Xuanwu Gate, they realized that something was wrong, and then wanted to flee quickly.

At this time, Li Shimin came out with his troops, and the King of Qi immediately wanted to shoot an arrow at Li Shimin, but because he was very panicked at that time, he did not shoot Li Shimin three times in a row, so Li Shimin shot at the prince, and Li Jiancheng died on the spot.
However, at this moment, Li Shimin's mount was out of control, and in the panic Li Shimin fell off his horse, and later Li Yuanji originally wanted to strangle him with a bow, but Wei Chigong saved Li Shimin and shot the King of Qi to death.
After the death of his brother, Li Shimin was still unwilling, and then he killed the prince and the sons and heirs of the King of Qi, and he really did a great job in this regard.
After everything had been arranged, he went into the palace to see his father.
Li Shimin explained things to his father, he killed his brother in the name of the prince's rebellion, and Li Yuan meant that it was exactly what he wanted in his heart!
After Li Shimin's continuous "efforts", Li Yuan finally abdicated, and Li Shimin also successfully ascended the throne.
In this incident, the role of Li Shimin seems to be very disgraceful, killing his brothers in order to ascend the emperor, and forcing his father to abdicate, but all this was caused by Li Yuan.
First, Li Yuan did not speak honestly of Li Shimin, because when he raised an army in Taiyuan, he promised Li Shimin that if he became emperor, he would make Li Shimin crown prince, but he did not do so.
Another point is that although Li Yuan supported the crown prince, at the same time he also allowed Li Shimin to cultivate power, and he wanted his two sons to contain each other to prevent either side from threatening his position.
Although Li Shimin made a lot of military achievements, Li Yuan's attitude was like not seeing it, and when the prince framed Li Shimin, Li Yuan also always favored the prince.
This situation made Li Shimin have a strong sense of resistance, and when Li Shimin knew that Li Jiancheng wanted to get rid of him, he wanted to attack first and then kill the two brothers.
I have to say that Li Shimin really played ruthlessness to wit, fortunately, he was very diligent after he took office, in short, he covered up the disgrace.