It is the collective term for the five main ethnic minority groups in the north during the late Western Jin dynasty—namely the Xiongnu, Xianbei, Jie, Di, and Qiang. These five ethnic groups had already lived in the northern grasslands and border areas before the unification of the Western Jin. Why is it that precisely after the War of the Eight Princes, they launched warfare and stirred up a catastrophe sweeping across the Central Plains? Without any single one of them, the upheaval of the Five Barbarians would not have occurred.