Its background was the "Yongjia Rebellion" at the end of the Western Jin Dynasty (that is, the "Five Wildflowers" incident in response to the national uprising in the Western Jin Dynasty after the five ethnic groups of Xiongnu, Xianbei, Jiedi and Qiang moved to the Central Plains). A large number of northern Han Chinese (including gentry, cloth landlords and a large number of civilians) were forced to move to the south of the Yangtze River and establish the Eastern Jin regime with Jiankang (now Nanjing) as its capital.

"People crossing the river" should refer to the gentry, the civilian landlord class who have the ambition to recover the northern Central Plains.