After Tang Gaozu acceded to the throne, Li Jian was the prince, Li Shimin was the king of Qin, and Li Yuanji was the king of Qi. Of these three people, Li Shimin contributed the most. Jinyang arise, is his idea; In the next few battles, he also made the greatest achievements. Li Gonggong was inferior, and only because he was the eldest son of Gaozu did he get the position of Prince. [ 1]
When the Prince made achievements, he knew that his prestige was not as good as that of Li Shimin, and he was jealous, so he teamed up with his younger brother, King Li Yuanji of Qi, to crowd out Li Shimin. [ 1]
After a long struggle, Li Shimin gradually gained the upper hand and controlled the situation. In the end, Li Shimin killed his eldest brother, Crown Prince Li, and his fourth brother, King Li Yuanji of Qi, and became the new Crown Prince, who succeeded him as emperor, for the sake of Emperor Taizong and Zhenguan.