Being the Sui Dynasty proved to be unpopular due to his tyranny. Liyuan ( 李渊 ) , an aristocratic official stationed in Taiyan ( 太原 ) , seized the opportunity to assume control of the capital, Chang'an. Taking advantage of the political turmoil and with the aid of his son, Li Shimin ( 李世民 ) , he declared himself emperor taking as his temple name Gauzu ( 唐高祖 ) . Over the next ten years all opposition to Emperor Gauzu was eliminated and his new regime effected a reunification of the whole of China in 628 AD. The Tang Dynasty, with its capital at Chang'an ( 长安 ) , the most populous city in the world at the time, is regarded by historians as a high point in Chinese civilization. Through the military exploits, its territory was greater than before.

The Tang period was the golden age of Chinese literature and art. A government system supported by a large class of Confucian literati selected through civil service examinations was perfected under Tang rule. But perhaps an even greater consideration for the Tang rulers, aware that imperial dependence on powerful aristocratic families and warlords would have destabilizing consequences, was to create a body of career officials having no autonomous territorial or functional power base. As it turned out, these scholar-officials acquired status in their local communities, family ties, and shared values that connected them to the imperial court. From Tang times until the closing days of the Qing Empire in 1911, scholar officials functioned often as intermediaries between the grassroots level and the government.

Li Shimin , later known as "Tang Taizong" ( 唐太宗 ) . Taizong then set out to solve internal problems within the government. Internal problems have constantly plagued past dynasties. The Emperor had three administrations ( 省 ): Military Affairs ( 尚书省 ) , Censorate ( 门下省 ) , and Council of State ( 中书省 ) . Each administration had its own duty.

Buddhism , originating in India around the time of Confucius ( 孔子 ) , continued to flourish during the Tang period and was adopted by the imperial family, becoming thoroughly sinicized and a permanent part of Chinese traditional culture.

The land distribution program of the Tang plays an important role of both their agricultural reform and their economic growth. The Tang wanted to gave life plots to the peasant families for ensuring that the families had enough land to both support themselves and to pay taxes. This system probably worked better in the north where wheat was grown than in the south; land was not so easy to divide and more labor was required for rice cultivation. The production of rice increased during this period rapidly. Techniques such as planting out seedlings rapidly increased yield. Early ripening varieties and a systematic selection of varieties helped to increase yield. Three important tools were developed to aid in rice cultivation: the chain with paddles which allow water to be transferred among levels, the harrow, and the rice field plough.