Liu Bang establishes the Han Dynasty (further divided into the Western Han by historians) and renames himself Emperor Gaozu. Liu Bang was one of the few dynasty founders in Chinese history who was born into a peasant family. Prior to coming to power, Liu Bang initially served for the Qin dynasty as a minor law enforcement officer in his home town Pei County, within the conquered state of Chu. With the First Emperor's death and the Qin Empire's subsequent political chaos, Liu Bang renounced his civil service position and became an anti-Qin rebel leader. He won the race against fellow rebel leader Xiang Yu to invade the Qin heartland and forced the surrender of the Qin ruler Ziying in 206 BCE.

During his reign, Liu Bang reduced taxes and corvée, promoted Confucianism, and suppressed revolts by the lords of non-Liu vassal states, among many other actions. He also initiated the policy of heqin to maintain a de jure peace between the Han Empire and the Xiongnu after losing the Battle of Baideng in 200 BCE.