Li Shimin's life story: 1, The Change of Xuanwu Gate. The change of Xuanwu Gate was a coup staged by Li Shimin, the second son of Tang Gaozu Li Yuan, near Xuanwu Gate, the North Palace of Taiji Palace in Chang 'an, Tang Dou (now Xi, Shaanxi) on the fourth day of June in Wude, Tang Gaozu. In the process of fighting against the Sui Dynasty, the cooperation between the Li brothers was tacit until the establishment of the Tang Dynasty. Tang Gaozu Tang Gaozu acceded to the throne, and Li Jian became a prince, who was stationed in the palace to handle affairs as a representative of the civil service group. Li Shimin, the king of Qin, continued to lead the military commanders to lead troops to fight, which was also the greatest contribution. Knowing that his merits and prestige were not as good as those of the people, the prince was afraid, so he joined forces with his younger brother, King Li Yuanji of Qi, to crowd out and frame Li Shimin. At the same time, Li Shimin Group also refused to accept the prince, and the two sides continued to fight with each other. After a long struggle, under the bias of others, Li Group gradually gained the upper hand and controlled the situation. In order to save the situation, he finally killed his eldest brother Li and his fourth brother Li Yuanji in Xuanwu Gate. For the sake of Emperor Taizong and Zhenguan, Li Shimin forced Tang Gaozu of Tang Gaozu to become the new Crown Prince and inherit the throne. 2. The rule of Zhenguan was the ruling situation of political clarity, economic recovery and cultural prosperity in the early years of Emperor Taizong. Emperor Taizong inherited Tang Gaozu's national policy of respecting ancestors and worshipping Taoism, and further developed it, ruling the country and leveling the world with Taoist thought. Emperor Taizong can be honest and make good use of others. Speak freely, respect life, exercise self-restraint, and be open-minded to teach; And adopted policies such as taking agriculture as the foundation, practicing economy, recuperating, reviving culture and education, and perfecting the imperial examination system to stabilize the society; And vigorously pacify foreign aggression, respect border ethnic customs, stabilize the border areas, and finally achieve the ideal situation of governing the world. Because the year number at that time was "Zhenguan" (627-649), it was called "Zhenguanzhi" in history. The rule of Zhenguan laid an important foundation for the prosperity of Kaiyuan and pushed China's traditional agricultural society to its peak.