Background
Li Shimin (Emperor Taizong) was born to mother Duchess Dou, and father Li Yuan (later to become Emperor Gaozu). At the age of 14 Li Shimin was married to the niece of Gao Shilian, an official in the then-ruling Sui dynasty. Two years later, in 615, Li Shimin joined the army in response to a call from Emperor Wen for men to assist against attacks from the Eastern Tujue. In 616 when Li Yuan was appointed governor of the major city Taiyuan, Li Shimin went with him. With the Sui dynasty beginning to collapse, Li Yuan and other officials began to fall into disfavor with Emperor Yang. Li Shimin secretly began to plot a rebellion against the Emperor with two of his father’s associates, Liu Wenjing and Pei Ji.Li Yuan agreed to the plan. Soon forces were consolidated and the capitol city Chang’an was captured.In 618 Li Yuan created the Tang dynasty and became Emperor Gaozu. He named Li Shimin as the Shangshu (in charge of executive government) as well as Prince of Qin. He also remained an active major general. As Qin Yang, he launched many military expeditions against his rivals. These successes allowed broad expansion of Tang territory. Li's two brothers grew envious and concerned. Prince Li Jiancheng specifically feared that Li Shimin would replace him. The fear drove him to fashion a plot to eliminate Li and grasp his military power. On July 2nd, 626 the brothers attempted a coup. Eventually it failed and Li Shimin and his forces killed the two brothers. Three days later, he became Prince. Two months later, Li Yuan abdicated in favor of Li, the latter becoming Emperor Taizong. This marked the start of the Zhenguan Reign considered one of the golden ages of Chinese history. He took the name Taizong in 626 when he became emperor. Trying to rule the country by law, he also promulgated Da Tang Lv (state law of Tang) which had a profound influence in Chinese history. Li Shimin also had highly developed literary taste. He composed many poems and was an accomplished calligrapher. In order to teach his offspring and memorialize his imperial experience, hewrote a book ca lled Di Fan (model of an emperor). Another important book called Zhen Guan Zheng Yao catalogued all of his administrative experience and became a reference book for monarchs and leaders in many other countries. In 649, Emperor Taizong contracted dysentery and soon after died at Hanfeng Palace in Chang'an.