Han Dynasty, Chinese dynasty (206 bc-ad 220), founded by Liu Bang (later Gao Zu) a humble soldier of fortune who became duke of Pei, later prince of Han, and subsequently (206 bc) emperor of China. The Han truly established China as a powerful unified state. Liu forged his empire, the Earlier (or Former/Western Han) in the succession struggle that followed the death of the first emperor, Shi Huangdi, and the breakup of his short-lived Qin (Ch’in) empire, taking Chang'an, now Xi'an (Sian) in Shaanxi (Shensi) Province, as his capital. He mitigated the Qin regime's harsh laws and heavy taxes, but retained its structure. Gao Zu also granted his family and allies large provinces in eastern China as subordinate kingdoms. Crucially for China's future, he made Confucianism the Han state ideology, though elements of divination and totalitarian Qin Legalism were added to buttress imperial rule. The Han followed the principle of appointment by merit, and a rudimentary examination system was instituted to test suitability for office. In the late 2nd century bc an imperial university was established which fixed the curriculum of Confucian classics.

Gao Zu's son Wendi (reigned 180-157 bc) continued his father's benevolent policies, and took back the land previously granted as kingdoms. The emperor Wudi (reigned 140-87 bc) put the nation's accumulated wealth to use. The Han expanded south of the Yangzi, absorbing land almost to China's modern borders, and planting colonies in Annam. Southern Dongbei and north Korea were subjugated, and forces battling the Hunnish Xiongnu nomads penetrated Central Asia as far as the Jaxartes River (Syr Darya in Kazakhstan). These costly campaigns led to tax increases, state monopolies over key industries like iron and salt production, and currency debasement. The booming population outgrew land supply. Wudi's reign ended messily in succession feuds and military defeats, and the highpoint of Han greatness passed.

The Earlier Han decayed in the 1st century bc, with several child emperors, nepotistic consorts, and government infighting. Great provincial families secured tax exemption, shrinking the state's fiscal base and shifting tax burdens on to the increasingly unruly peasantry. Finally Wang Mang (died ad 23), a courtier and regent for the last infant emperor of the Earlier Han, seized the throne, beginning the brief Xin Dynasty interregnum (ad 9-23). Seeking popular support, Wang nationalized tax-exempt estates and redistributed them to the peasantry, expanded state monopolies, and abolished slavery. Landowner resistance ended his policies in the teeth of an agrarian crisis worsened by the impoverished state's neglect of water systems in north China. Rebellious northern peasants, known as the Red Eyebrows, joined with the great families, stormed Chang'an, and killed Wang Mang.

Liu Xiu (later Guangwudi), the 15th Han emperor, re-established the dynasty as the Later (or Eastern) Han (ad 25-220), and moved the capital to Luoyang (Lo-yang) in Henan (Ho-nan) Province. He restored the Earlier Han governmental structure, but from around ad 100 this once again deteriorated. Eunuchs became more powerful and began feuding savagely with government officials, briefly triumphing in ad 186, only to be massacred three years later. Classical Daoism had by now mutated into a popular religion which spawned two huge rebellious sects, the Yellow Turbans in Shandong, and the Five Pecks of Rice Society in Sichuan, which were not subdued until ad 215. The anti-rebel mobilization spurred growing provincial autonomy, and in ad 220 the weakened empire finally split into three, the so-called Three Kingdoms. There were 14 Earlier Han emperors and 12 Later Han emperors.