Following the fall of the Western Jin dynasty (215–316 CE), there was mass migration to the south of China, to below the Yangtze River. The Eastern Jin dynasty was established; Sima Rui named himself Emperor Yuan of Jin in 317 CE and established the capital at Jiankang. The Eastern Jin’s aim was to reclaim some of the northern territories, yet the dynasty was plagued by instability, weakness and corrupt military figures. The north comprised a series of fractured sovereign states, some of the last of the era of the Sixteen Kingdoms. Ruled by nomadic tribal people, the northern states also sought territorial expansion to the south but their lack of political unification hindered any potential success against the Eastern Jin.