Li Shimin was the emperor of the Tang Dynasty. He and his father, Tang Gaozu Li Yuan, fought together in Taiyuan and gradually developed into the largest gate valve. Finally, the separatist forces were eliminated, and the uprising troops were taken over, and finally the prosperous time of the Tang Dynasty was established. In the process of establishing the Tang Dynasty, although Li Yuan proclaimed himself emperor, Li Shimin played an important role. It can be said that most of the world in Li Tang was filmed by Li Shimin. Most of the civil servants and military commanders in Li Tang were summoned by Li Shimin.

When Tang Gaozu proclaimed himself emperor, named Li Jian prince and Li Shimin king of Qin, many generals were dissatisfied with Li Shimin. However, Li Shimin kept his hair until the change of Xuanwu Gate, which killed Prince Li Chengjian and his third brother Li Yuanji in one fell swoop and took control of the whole court. Tang Gaozu had no choice but to canonize Li Shimin as a prince and later cede the throne to him. After Li Shimin acceded to the throne, he exercised strict self-discipline, handled state affairs in an orderly way, and the monarch and his subjects were United. Finally, he achieved good results in the rule of Zhenguan, and was named Tiankhan by Hu Min in the north.

As the saying goes, people are doing, and the sky is watching. Li Shimin failed to educate his son well. Li Chenggan, Prince of Li Shimin, is his favorite son. He received a serious education since he was a child, and even studied under the famous remonstrator Wei Zhi at that time. Li Chenggan was very sensible when he was a child, but he rebelled when he grew up. First of all, I didn't take Wei Zhi's teachings to heart, and then I went my own way and even made a fool of myself.

In order to educate him, Li Shimin severely criticized and educated Li Chenggan. But for the sake of prosperity, Li Chenggan finally thought of a superior way for his father: regicide. So, Li Chenggan colluded with the general Hou, and did a regicide to seize the throne. Although things were stopped by Li Shimin and Li Chenggan was abandoned as a civilian and exiled, the whole process made everyone feel the helplessness of Li See citizens. It is a failure to educate my son.