Academically, the period of the Three Kingdoms refers to the period between the foundation of the state of Wei in 220 AD and the conquest of the state of Wu by the Jin dynasty in 280. The earlier, "unofficial" part of the period, from 184 to 220, was marked by chaotic infighting between warlords (军阀) in various parts of China. The middle part of the period, from 220 to 263, was marked by a more militarily stable arrangement between three rival states of Wei, Shu, and Wu. The later part of the era was marked by the conquest of Shu by Wei (263), the usurpation of Wei by the Jin dynasty (265), and the conquest of Wu by the Jin (280).