The first emperor who unified China in terms of ideology was none other than Han Wudi
Emperor Wu of the Western Han Dynasty
In order to consolidate his rule, he proscribed all non-Confucian schools of thought and espoused Confucianism as the state ideology, thus pushing Confucius up into the orthodox position. For two thousand years thereafter, Confucianism had been the only one dominant school of thought in China.
Han Wudi, named Liuche, ascended the throne at the age of 15. He was the fifth emperor of the Western Han Dynasty (206BC-8AD) and reigned from 141BC to 86BC, which is one of the most celebrated periods in Chinese history.
During the period of Wen and Jing emperors before Han Wudi, China was peaceful and prosperous -- population grew greatly and industry and commerce were developed. Han Wudi, son of Emperor Jin, carried out a series of reforms and devoted himself to military conquests and territorial expansion.
Han Wudi's most important military campaigns were against the Hun, an ancient tribe that lived in North China who posed a powerful threat to the Han Empire. After three expeditions, Han Wudi finally drove the Hun into the far north of Gobi, thus maintaining the safety of the Hexi Corridor. In order to avoid the aggression of other nomadic tribes, Han Wudi also ordered the construction of the Great Wall.
In 138 BC, Han Wudi sent Zhang Qian -- Chinese ambassador-- with a diplomatic expedition to Central Asia to try to find allies against the Hun. Failing to achieve his original purpose, Chinese ruler became aware of the cultures and customs of other nationalities. Eventually, this led to the opening of the Silk Road, which later served as a route for cultural and economic exchange between the east and the west.
Han Wudi accepted Dong Zhongru's proposal of "rejecting the other schools of thought and respecting only Confucianism" which ended the period of "contention among one hundred schools of thought". Afterwards, Confucian...