In 295, Tuoba Luguan the chieftain of the Tuoba (a branch of the Xianbei) divided the territory under Tuoba control into three areas: a vast tract of land extending west from White Mountain (northeast of Zhangjiakou), to Dai (Datong, Shanxi); an area from Shengle (south of Hohhot) and beyond; and a central area, which included north Shanxi and the region to its north.
As chieftain of the western Tuoba territory, Tuoba Yilu defeated the Xiongnu and Wuhuan to the west, gaining in this way the support of various ethnically Han and Wuhuan people, in addition to his own Xianbei people.
The name Dai itself originated when Tuoba Yilu was created Duke of Dai (代公) and rewarded with five commanderies by the Western Jin in 310 as a reward for his helping Liu Kun (劉琨), the Governor of Bingzhou (并州) (modern Shanxi province), to fight the Xiongnu Han state.
[2] This fief was later raised from a duchy to a principality by the Western Jin court in 315.
In 312, Tuoba Yilu assisted Liu Kun in the recapturing of Jinyang (晉陽, in modern Taiyuan, Shanxi) from the Han general Liu Yao.