Wu, known in historiography as Eastern Wu or Sun Wu, was a dynastic state of China and one of the three major states that competed for supremacy over China in the Three Kingdoms period. It previously existed from 220 to 222 as a vassal kingdom nominally under Cao Wei, its rival state, but declared complete independence from Cao Wei in November 222. It was elevated to an empire in May 229 after its founding ruler, Sun Quan, declared himself emperor.

For most of its history, China was organized into various dynastic states under the rule of hereditary monarchs. Beginning with the establishment of dynastic rule by Yu the Great c. 2070 BC, and ending with the abdication of the Xuantong Emperor in AD 1912, Chinese historiography came to organize itself around the succession of monarchical dynasties. Besides those established by the dominant Han ethnic group or its spiritual Huaxia predecessors, dynasties throughout Chinese history were also founded by non-Han peoples.