 Sima Dewen abdicated in 420 in favor of Liu Yu, who declared himself the ruler of the Song; Sima was asphyxiated with a blanket the following year.In the north, Northern Liang, the last of the Sixteen Kingdoms, was conquered by the Northern Wei in 439, ushering in the Northern dynasties period.The Xianbei Northern Wei accepted the Jin refugees Sima Fei () and Sima Chuzhi ().