Kings of the Han dynasty
The kings from other dynasties (, "yìxìng wáng") were mostly remnants of the rebellion against the Qin dynasty. Following the Dazexiang Uprising, many noblemen rose in rebellion. Heirs, pretenders, and warlords called themselves "kings" and claimed sovereignty as continuations of the six states previously suppressed by Qin. Among these, Chu was the most powerful. However, its rightful ruler Huai II was assassinated on the orders of the warlord Xiang Yu and the 18 Kingdoms Xiang had formed rose in rebellion against him. Liu Bang, king of Han, ultimately defeated Chu and established the new Han dynasty. The kings who had sided with him were then permitted to maintain their titles and lands. A few other kingdoms were also formed by Liu Bang for generals and favorites.
Battle of Xiaoting
On 25 November 220, Emperor Xian, the figurehead monarch of the Eastern Han dynasty, abdicated in favour of Cao Pi and ended the Eastern Han dynasty. On 11 December, Cao Pi established the state of Wei to replace the Eastern Han dynasty and became its first emperor. On 10 May 221, Liu Bei declared himself emperor at Wudan (武擔; a hill in the northwest of present-day Chengdu, Sichuan) and established a new state, historically known as Shu, to contest Cao Pi's claim to the Han throne. Around the same time, Sun Quan shifted the capital of his territories from Gong'an County to E County (鄂縣; present-day Ezhou, Hubei), which he renamed "Wuchang" (武昌). On 23 September 221, Sun Quan pledged allegiance to Cao Pi and became a vassal of the Wei state; in return, Cao Pi awarded Sun Quan the title "King of Wu" (吳王).