The Han dynasty conventionally ruled China from 206 BC to AD 220, making it one of the longest major dynastic periods in ancient Chinese history. The dynasty began when Liu Bang established the Han state after the collapse of the Qin dynasty and the civil conflicts that followed. It ended when Emperor Xian abdicated in AD 220, after which China entered the politically fragmented period known as the Three Kingdoms. The dynasty is usually divided into two principal phases.
The Western Han lasted from 206 BC to AD 9 and was centred mainly on Chang'an. The Xin dynasty of Wang Mang interrupted Han rule from AD 9 to AD 23. The Eastern Han then ruled from AD 25 to AD 220, with its capital at Luoyang. Because of this interruption, the phrase Han dynasty covers two periods of rule separated by a short but historically important regime.
The Western Han began after Liu Bang defeated his principal rival Xiang Yu and consolidated power. Liu Bang became Emperor Gaozu and established institutions that combined Qin style central administration with policies intended to reduce some of the harshness associated with Qin rule. Early Han rulers faced the challenge of controlling territories that had previously been distributed among rival kings. Some areas were granted to members of the imperial family and influential supporters, creating semi autonomous kingdoms.
The central government gradually reduced the power of these kingdoms, particularly after conflicts demonstrated their potential threat to imperial authority. By the middle of the Western Han, the emperor and central bureaucracy exercised substantial control over the empire. The Western Han period laid the institutional foundation for later Han expansion and cultural development.
The reign of Emperor Wu from 141 to 87 BC marked a major transformation in Han power. Emperor Wu strengthened the central government, expanded military operations against the Xiongnu and extended Han influence into Central Asia, northern Vietnam and the Korean Peninsula. The state became more interventionist in economic affairs, including regulation of salt and iron and management of grain supplies.
Emperor Wu also promoted Confucian learning within government institutions, helping establish an enduring connection between classical education and official service. These policies expanded the territorial and administrative reach of the Han state but also placed substantial financial demands on the population. Later Western Han rulers attempted to manage these pressures while powerful families became increasingly influential.
The Xin dynasty interrupted Han rule from AD 9 to AD 23. Wang Mang, a powerful court official and member of the imperial family by marriage, took control and established the Xin dynasty. He introduced a series of ambitious reforms involving land, currency, taxation and state regulation. Some reforms were intended to address social inequality and the concentration of land, but implementation was difficult and resistance developed among different groups. Natural disasters, flooding and economic disruption contributed to instability. Rebellions including the Red Eyebrow movement weakened the regime, and Wang Mang was eventually killed in AD 23. The Han dynasty was subsequently restored, although political authority and the imperial centre had to be reconstructed.
The Eastern Han began formally in AD 25 under Liu Xiu, later known as Emperor Guangwu. He was a descendant of the Han imperial family and successfully defeated competing forces after the fall of Wang Mang. He restored the dynasty but moved the capital from Chang'an to Luoyang, which became the political centre of the Eastern Han. Early Eastern Han rulers rebuilt administrative institutions and reasserted control over much of the former Han territory. The period continued to see military activity along the northern and western frontiers, diplomatic relations with neighbouring states and economic development. Eastern Han China remained a major imperial state, although powerful families increasingly gained influence over land, offices and local administration.
The later Eastern Han experienced growing political instability. The imperial court became divided among competing groups, including powerful consort families, eunuch officials and scholar officials. Emperors sometimes came to the throne as children, increasing the influence of regents and palace factions. Local magnates acquired substantial land and economic resources, while ordinary farmers faced taxation, labour demands, debt and environmental crises. The Yellow Turban Rebellion in AD 184 exposed the weakness of central authority and required military commanders to mobilise large forces. Although the rebellion was suppressed, regional warlords gained greater independence. The Han court increasingly depended on military leaders whose power could not easily be controlled by the emperor.
The final decades of Han rule were dominated by competition among regional military figures. Dong Zhuo seized control of the imperial court in AD 189 and moved the emperor, contributing to further instability. After Dong Zhuo's death, powerful warlords including Cao Cao, Liu Bei and Sun Quan competed for territory and influence. Cao Cao gained control over the Han emperor and used the emperor's authority to legitimise his own political position, although he did not formally end the dynasty.
After Cao Cao's death, his son Cao Pi forced Emperor Xian to abdicate in AD 220 and established the state of Wei. Liu Bei established Shu Han, while Sun Quan established Eastern Wu, producing the political division known as the Three Kingdoms. The end of Han rule was therefore a gradual process of political fragmentation rather than a single external conquest.
The Han dynasty's chronological importance extends beyond its dates because later Chinese political culture repeatedly looked back to the Han as a model of imperial government. Its four centuries of rule established durable institutions involving central administration, taxation, military organisation, education and historical writing. The Western and Eastern Han periods also witnessed major developments in territorial expansion, trade, technology and culture.
The interruption by the Xin dynasty demonstrates that dynastic continuity could survive even after a brief change of ruling house, while the eventual collapse in AD 220 illustrates the vulnerability of large imperial systems to factional conflict, economic inequality, military decentralisation and environmental crisis. The conventional dates of 206 BC to AD 220 therefore describe a period containing major internal transformations rather than a completely continuous political system.
