The second emperor of the Tang Dynasty (618 - 907), Emperor Taizong ('Supreme Ancestor') Li Shimin was a great emperor, militarist, politician and calligrapher in Chinese History. He was the second son of Emperor Gaozu and Empress Dou. He was given the name 'Li Shimin' because a physiognomist foretold that he would benefit the age and pacify the masses later, when he was four years old.
In 615, Emperor Yangdi of the Sui Dynasty (581 - 618) was besieged in Yanmen (Dai County of Shanxi Province) by a Turkic group. At that time, when he was only 16 years old, he rescued Emperor Yangdi and caught the Turkic Khan That was his first time to stand out.
In 617, Li Yuan, Emperor Taizong's father, was appointed governor of Taiyuan. By then, the Sui Dynasty had declined, and Li Shimin took the chance to develop financial strength, recruit soldiers and buy horses, getting ready to array his army against the Sui Dynasty to seize the control of China. Li Shimin's close friend Liu Wenjing, County Magistrate (Xianling) of Taiyuan, was imprisoned because of being involved with the Wagang rebels. Under the guise of a visit, Li Shimin entered the prison and drafted the plans to establish another dynasty, after which he told his plans to his father Li Yuan. After Li Yuan started the war in Taiyuan, Li Shimin and his brother Li Jiancheng led two groups of soldiers, fighting together with their father.
Finally, in November of 617, they captured Chang'an (currently Xian), and established the Tang Dynasty the next year.
After the establishment of the Tang, Li Shimin became King Qin. Later, Li Shimin's military exploits surpassed those of Prince Li Jiancheng and Kin Qi – Li Yuanji during the unifying wars of the whole country. First, he defeated Xue Ju who occupied Jincheng (Lanzhou of Gansu Province), and made Xue Ju surrender to the Tang Dynasty. Then, he beat off Liu Wuzhou and Song Jingang depending on the Turkic force. In 621, he beat Dou Jiande and destroyed the Xia Dynasty. In addition, he forced Wang Shichong to surrender to the Tang; the Zheng regime ended with him. However, he was the second son of Li Yuan and couldn't inherit the throne. Meanwhile, Prince Li Jiancheng was threatened by Li Shimin's great contributions. Thus, struggles for the throne expanded between Li Shimin and Li Jiancheng, Li Yuanji.
On July 2nd of 626, Li Shimin launched a palace coup at the Xuanwumen Gate. On that day, Emperor Gaozu called Li Shimin, Li Jiancheng and Li Yuanji to the palace. Li Shimin and his follower Yuchi Jingde led a group of soldiers and lurked at Xuanwumen Gate which was the way Jiancheng and Yuanji had to take to the palace. When Jiancheng and Yuanji came to the gate, they found that the familiar guard leader of the gate was missing and the other guards were also very strange.
They suspected that there might be something wrong. When they were very close to the gate, the guards asked them to leave their bodyguards and weapons and to respect Li Yuan themselves. On hearing that, Li Jiancheng turned his horse quickly to escape. Just then, Li Shimin cried:"Stop" behind and rode a horse to catch up with him. Under that situation, Li Jiancheng tried his best to run away, but was shot by an arrow from Li Shimin from behind. Seeing that, Li Yuanji drew his arrow to shoot Li Shimin, but failed several times because of nervousness. Later, Yuchi Jingde came with 70 cavalries, and shot Li Yuanji down from the horse. Li Yuanji was frightened and intended to escape, but was killed by Yuchi Jingde in the end.
Li Yuan was waiting for his three sons in the palace, but found that the outside fell into a mess suddenly. Yuchi Jingde led a group of soldiers came into the palace before Li Yuan found out what had happened. He reported to Li Yuan that Li Jiancheng and Li Yuanji were both killed by King Qin because of scheming to rebel, and King Qin had assigned him to protect Li Yuan from the disordered soldiers. Meanwhile, he again forced Li Yuan to order the guards of Li Jiancheng and Li Yuanji to stop their resistance. Hearing that, Li Yuan was shocked and irritated. However, he had to accept the truth and make Li Shimin prince. Knowing that the situation was beyond saving, he passed the throne to Li Shimin two months later.
In 627, Li Shimin changed his reign title to 'Zhenguan' in 627, and began his reign formally.
Drawing a lesson from the decline of the Sui Dynasty, Li Shimin was alert to the challenges which lay ahead, gave important positions to wise, capable and virtuous persons, and accepted others' good advice and ideas after ascending to the throne. In addition, he reduced all sorts of taxes, mitigated punishments, and carried out a series of reforms in politics and the military. Through his effort, the society showed signs of prosperity. So his ruling period was named the 'Zhenguan Era'.
During his rule, Li Shimin recaptured several minority groups in order to create a peaceful inner developing environment. In 630, he assigned General Li Jing to pacify the Eastern Turks, and release the threat in the north. In 635, he defeated Tu Gu Hun. In 640, he sent General Hou Junji to pacify the Gaochang Group, and set up a protectorate at Jiaohe City called Anxi Duhufu. Li Shimin adopted enlightened policies to treat recaptured minorities, received their respect, and was respected as the 'Heaven Khan'. Later, he sent Princess Wencheng to marry Songzanganbu, king of the Tubo Kingdom, to develop friendly communications with the Tibetian people.
Domestically, he paid close attention to the common people's lives. He compared the people and himself to be the water and the boat, and thought that the water could both bear and swallow the boat. So he cherished the labor forces and never requisitioned them randomly. Meanwhile, he was economical himself. He suffered from joint disease, but he kept living in damp and old palaces for a long time. In selecting talents, he continued to adopt the 'Imperial Exam System' of the Sui Dynasty. He was eager to find wise persons, and had even published talent-seeking orders five times. At the same time, he increased the subjects of the exam, and enlarged the scale and number of the examinees in order to discover more excellent personnel. As a result, excellent persons came forth in a great number during the Zhenguan period, and they made great contributions in promoting the form of the 'Zhenguan Era'.
In politics, he further developed and perfected the System of Three Cabinets and Six Departments. In business, unlike the former dynasties, Li Shimin provided lots of good conditions for the development of business. Then, over half of the noted cities were gathered in China. Besides the coastal cities of Guangzhou and Fuzhou, there were many inland prosperous cities such as Hongzhou (Nanchang of Jiangxi Province), Yangzhou, Yizhou (Chengdu), Shazhou (Dunhuang), Liangzhou (Wuwei of Gansu Province) as well as the capital city Chang'an.
In addition, the Tang Dynasty in the Zhenguan Period was a rare wide-open dynasty in Chinese History. Then, the western world became fragmented because of the ruin of the Roman Empire, while the Tang Dynasty was just at its most prosperous time under the wise reign of Emperor Taizong. The Tang State then was the 'Sun Area' in the hearts of people all over the world. Travelers and businessmen from all nations risked their lives to come to China. So Chang'an became a world metropolis. Meanwhile, the rising city Guangzhou was also crowded with thousands of foreigners. At that time, the Tang Dynasty not only received foreign immigrants; they also received groups of foreign students to China to learn advanced culture. Among them were hundreds of Japanese students who studied at public expense.