Li Yuan has many children, the most famous of which are Li Shimin, Li Yuanji, and Li Jiancheng, and the competition between these three children can be called a wonderful history. And the pinnacle of this family feud occurred in the Xuanwumen Change.
Many people wondered why Li Yuan had given the responsibility of commanding such a strong army to Li Shimin instead of Li Jiancheng. It seems that Li Yuan regards the crown prince Li Jiancheng as the best heir, but suddenly let Li Shimin hold the power of the heavy army, did Li Yuan not consider the possibility of controlling Li Shimin?History tells us that when Li Yuan ruled the world, Li Shimin made great achievements on the battlefield of the Eastern Expedition, and his prestige surpassed that of Li Jiancheng. Li Jiancheng was jealous of Li Shimin, so he joined forces with Li Yuanji, the king of Qi, in an attempt to exclude Li Shimin. And Li Shimin himself was unwilling to accept the rule of the crown prince, and through a series of open and secret battles, he was finally persuaded by the strategists around him to launch the Xuanwumen Change. In this thrilling rebellion, Li Shimin personally shot his brother Li Jiancheng.
* Kui, in terms of martial arts, Li Jiancheng is not inferior to his father Li Yuan. In the early days of Li Yuan's uprising, the garrison generals in Hexi had become a huge potential threat. Li Yuan ordered Li Jiancheng to be the commander-in-chief and Li Shimin to be the deputy, and jointly lead the army to conquer. Li Jiancheng also realized that the Tang army had just been established and had not yet undergone formal military training, so he ordered a rectification. He not only personally supervised the training, but also lived with the soldiers, and severely punished all indisciplined behavior. Li Shimin's achievements today are also inseparable from the way of governing the country that he learned from Li Jiancheng.
Li Jiancheng won overwhelming victories in many battles, including the Liu Heimin Rebellion and the Liu Yan Rebellion. Politically, he inherited his father's benevolent style, but he did not make concessions in the way of governing the country, even in the face of Li Yuan's mistakes, he could not hesitate to point out, rather than blindly obey. Therefore, in Li Yuan's mind, Li Jiancheng gradually became a more promising candidate to inherit the throne. Many people were loyal to Li Jiancheng, such as Wang Qi, Wei Zheng, and even most of the big families in Longxi also supported him. The Book of the Old Tang Dynasty does not mention anything about this history, but it also proves that Li Jiancheng is indeed an outstanding heir.
As the eldest son, Li Jiancheng is justifiable, and he has performed well in the position of crown prince, so there is no reason to be abolished at all. However, if Li Shimin wants to ascend to the throne, the only way is to get rid of Li Jiancheng. In the long course of history, emperors were essentially divided into Emperor Wu and Emperor Wen. Emperor Wu was mostly a monarch who fought on horseback, rather than reviewing and reciting in the court. After Li Jiancheng inherited the throne, he was also worried about the threat of Li Shimin, so he did not go into battle in person, but stayed in the rear to preside over the government, maintain the stability of the Tang Dynasty, and provide solid logistical support for the front line. This is also the reason why Li Shimin was able to obtain military power and was supported by soldiers, mainly due to Li Yuan's preference for Li Jiancheng.
To sum up, Li Yuan believes in his heart that Li Jiancheng is the best heir. However, Li Shimin's prestige and talent are too strong. The royal court is a dangerous and ** place, what Li Jiancheng, Li Yuan and Li Shimin did is not a heinous crime, the only problem is that the Tang Dynasty conspiracy blinded them and made them unable to see the true goodness.