Editing Northern and Southern dynasties (section)

==Background==
{{main|End of the Han dynasty|Three Kingdoms|Jin dynasty (266–420)|Upheaval of the Five Barbarians|Sixteen Kingdoms}}
After the collapse of a unified [[China proper]] under the [[Han dynasty#Eastern Han|Eastern Han dynasty]] in 220 due in large part to the [[Yellow Turban Rebellion|Yellow Turban]] and the [[Way of the Five Pecks of Rice|Five Pecks of Rice]] rebellions, China eventually coalesced into the [[Three Kingdoms]]. Of these, [[Cao Wei]] was the strongest, followed by [[Eastern Wu]] and [[Shu Han]], but they were initially in a relatively stable formation. After a 249 [[Incident at the Gaoping Tombs|coup]] by [[Sima Yi]], the Sima family essentially controlled Cao Wei and the [[conquest of Shu by Wei|conquest of Shu Han by Cao Wei]] followed in late 263.

Following [[Sima Zhao's regicide of Cao Mao|a failed coup]] by the ruling Cao family against the Sima family in June 260, the final Cao ruler abdicated in February 266. [[Emperor Wu of Jin|Sima Yan]] (Emperor Wu of Jin) then founded the [[Jin dynasty (266–420)|Western Jin dynasty]] and the [[conquest of Wu by Jin|conquest of Eastern Wu by Western Jin]] occurred in 280, ending the Three Kingdoms period and reuniting China proper.

The Western Jin dynasty was severely weakened due to the [[War of the Eight Princes]] from 291 to 306. During the reigns of [[Emperor Huai of Jin]] and [[Emperor Min of Jin]], the empire was put into grave danger by the uprising of northern non-Han peoples collectively known as the [[Five Barbarians]]. Numerous nomadic tribal groups had been forcibly resettled in northern and northwestern China during previous centuries. When the warring princes heavily drafted these tribes into the military, they mutinied and exploited the civil wars to seize power.<ref>{{cite book |last1=Jacques Gernet |title=A History of Chinese Civilization |url=https://archive.org/details/historyofchinese00gern_0 |url-access=registration |date=1996 |publisher=Cambridge University Press |isbn=0521497817 |page=[https://archive.org/details/historyofchinese00gern_0/page/180 180] |edition=illustrated, reprint, revised}}</ref> Their armies almost destroyed the dynasty in the [[Disaster of Yongjia]] of 311, when the Five Barbarians sacked [[Luoyang]]. [[Chang'an]] met a similar fate in 316.

However, a scion of the imperial house, [[Emperor Yuan of Jin|Sima Rui]] (Emperor Yuan of Jin) fled south of the [[Huai River]] and reestablished the dynasty, known in historiography as the [[Jin dynasty (266–420)#Eastern Jin (317–420)|Eastern Jin dynasty]]. Cementing their power in the south, the Eastern Jin established [[Jiankang]] on the existing site of Jianye (now [[Nanjing]]) as their new capital.

In the north, the Five Barbarians established numerous short-lived dynasties, leading to the period known as the [[Sixteen Kingdoms]] in historiography. Eventually, the [[Northern Wei|Northern Wei dynasty]] conquered the rest of the northern states in 439 and unified northern China. Although the Eastern Jin and successive southern dynasties were well-defended from the northern dynasties by their placement of naval fleets along the Yangtze, they suffered various problems related to the creation and maintenance of military strength. The court's designation of specific households for military service through the [[tuntian]] system eventually led to a fall in their social status, causing widespread desertion of troops. Faced with shortage of troops, Eastern Jin generals were often sent on campaigns to capture non-Han indigenous peoples in the south to draft them into the military. The Eastern Jin dynasty fell not because of external invasion, however, but because [[Emperor Wu of Song|Liu Yu]] (Emperor Wu of Liu Song) seized the throne from the [[Emperor Gong of Jin]] and founded the [[Liu Song dynasty]], which officially began the Northern and Southern dynasties period.