During his reign, he practiced the system of officers and men, the system of renting mediocrity and the system of land equalization, and actively promoted the imperial examination system. In 630, he defeated the Turks and was honored as "Tiankhan" by the Turkish ministries. In 64 1 year, Princess Wencheng was married to Tubo Songzan Gambu. Prince Li Zhi was appointed as an agent in Jinyemen. In July, 649, Li Shimin died in Chang 'an Hanfengtang. He was buried in Zhaoling, more than 50 miles northeast of Shaanxi Liquan. Posthumous title is "Emperor Wen". Emperor Taizong was good at listening to the criticisms and opinions of ministers, and Zheng Wei directly pointed out his mistakes more than 200 times. Emperor Taizong was also good at calligraphy, writing tablets with lines, and was the originator of later generations. His famous works include Hot Springs and Hot Springs. Open the way, modestly coachable, reuse Wei Zhi, etc. He also adopted policies such as taking agriculture as the foundation, reducing taxes, recuperating, practicing economy and perfecting the imperial examination system, so as to make the society peaceful. He later stood side by side with Li Longji's Kaiyuan Shi Sheng. Li Shimin, Emperor Taizong, reigned for 23 years, which made the Tang Dynasty enjoy economic development, social stability, political clarity, people's prosperity and well-being, and unprecedented prosperity. Therefore, people call this period of his rule "the rule of Zhenguan". The rule of Zhenguan is the most dazzling period in the history of China. Emperor Taizong absorbed the reasons for the demise of the Sui Dynasty and attached great importance to the lives of ordinary people. He emphasized people-oriented, and often said: "People, water is also; Jun, Zhou Ye. Water can carry a boat or overturn it. " At the beginning of Emperor Taizong's accession to the throne, he ordered the people to recuperate. Emperor Taizong cherished the people's resources and never levied corvees easily. He suffered from Qi disease and was not suitable to live in a damp old palace, but he lived in the old palace of the Sui Dynasty for a long time. At the beginning of Zhenguan, under the leadership of Emperor Taizong, the monarch and ministers were in harmony, the whole country was United as one, and the economy improved rapidly. By 1989, cattle and horses were everywhere, and the people were well-fed and kept indoors at night. More than 30 officials protested, including Minister Wei Zhi. His protests included more than 200 events and hundreds of thousands of words, which hit the nail on the head and were very helpful for improving state affairs. Emperor Taizong attached great importance to the selection of talents and strictly followed the principle of having both ability and political integrity. Tang Taizong believed that only by selecting a large number of people with real talents and practical learning could he achieve great achievements in the world. So he was thirsty for talent and awarded the imperial examination five times. Because Emperor Taizong attached great importance to talents, a large number of outstanding talents emerged in Zhenguan period, which can be described as "talented people come forth in large numbers, both civil and military". It is these pillars that have made great contributions to the formation of "Zhenguan rule" with their intelligence and wisdom. Emperor Taizong attached great importance to the rule of law. He once said: "The national law is not the law of the emperor alone, but the law that the whole world must abide by, so everything must be observed." Take the lead in obeying the law and maintain the unity and stability of the law. During the Zhenguan period, the prince did commit crimes against the people. When enforcing the law, he was impartial, but when sentencing, Taizong thought twice and was cautious. He said: "People can't be resurrected after death, and law enforcement must be combined with leniency and severity." Due to the painstaking efforts of Emperor Taizong, the legal system in Zhenguan period was very good, with few people breaking the law and being sentenced to death. According to records, Emperor Taizong was sentenced to death. Reuse talents and appoint people on their merits is the criterion; Impatience and selflessness, and the tolerance of doing things according to law; It constituted the basic characteristics of Zhenguan rule and became the best example of feudal rule, which made the Tang Dynasty walk in the forefront of the world in politics, economy and culture compared with the western countries at that time.