《资治通鉴·晋纪·晋纪五》
 等到周王朝失去纲纪，诸侯恣意征伐，因此，彼此的疆域不稳定，诸侯因为利害关系而各存异心，西戎、北狄得以乘隙进入中原，有的诸侯招抚利诱他们为自己所用，从此四方各族交相杂入，与中原人错综而居。
 及至周室失统，诸侯专征，封疆不固，而利害异心，戎、狄乘间，得入中国，或招诱安抚以为己用，自是四夷交侵，与中国错居。
When the Zhou Dynasty lost order and the princes fought recklessly, their territories became unstable, and the princes harbored different intentions due to their conflicting interests. The Xirong and Beidi took advantage of this opportunity to enter the Central Plains. Some princes welcomed them and used them to their own advantage, and since then, the various tribes have mingled with each other and lived together in the Central Plains.