Three Kingdoms period The three kingdoms were Wei, Shu, and Wu. To help further distinguish these states from other historical Chinese states of the same name, historians add a relevant character: Wei is also known as Cao Wei, Shu is also known as Shu Han, and Wu is also known as Dong Wu or Eastern Wu.

The earlier, "unofficial" part of the period, from 184 to 220, was marked by chaotic infighting between warlords in various parts of China. The middle part of the period, from 220 and 263, was marked by a more militarily stable arrangement between three rival states, Cao Wei, Shu Han, and Eastern Wu. The later part of this period was marked by the collapse of the tripartite situation: first the destruction of Shu by Wei (263), then the overthrow of Wei by the Jin Dynasty (265), and the destruction of Wu by Jin (280).

The Three Kingdoms period was one of the bloodiest in Chinese history. A population census during the late Eastern Han Dynasty reported a population of approximately 50 million, while a population census during the early Western Jin Dynasty (after Jin re-unified China) reported a population of approximately 16 million.