Absorbing the Xiongnu steppe
93
After the Northern Xiongnu collapse, the Xiongnu tribes remaining on the plateau joined the Xianbei, per Chinese accounts, they 'became Xianbei'.
93 – 235 AD
After the Northern Xiongnu fell, the Xianbei became masters of the steppe. Tanshihuai (r. c. 156–181) united them, ruling from Liaodong to Dunhuang. The Xianbei are generally regarded as proto-Mongolic speakers, giving them a special place in Mongolian ethnic history.
Ends in 235, when Kebineng was assassinated and the confederation broke up. Wikipedia gives 234.
The Xianbei polity was a confederation rather than a centralized empire and fragmented quickly after Tanshihuai's death. The Cambridge History (Sinor 1990) has no dedicated Xianbei chapter; Atwood's encyclopedia is the main reference.
This period has a page and its sources; the scroll-through chapter is not written yet.
93
After the Northern Xiongnu collapse, the Xiongnu tribes remaining on the plateau joined the Xianbei, per Chinese accounts, they 'became Xianbei'.
c. 156–181
Tanshihuai united the Xianbei tribes, organized them into three wings, and raided the Han frontier relentlessly.
235
After Kebineng was assassinated in 235 the united confederation dissolved; Xianbei successor houses, Murong, Tuoba, later dominated north China (the Tuoba founding the Northern Wei, 386–534).