Xiongnu
The Xiongnu () were a confederation of nomadic peoples who, according to ancient Chinese sources, inhabited the eastern Asian Steppe from the 3rd century BC to the late 1st century AD. Chinese sources report that Modu Chanyu, the supreme leader after 209 BC, founded the Xiongnu Empire.
Wuhuan
In 209 BC, Modu Chanyu, founder of the Xiongnu empire, defeated the Donghu. The Wuhuan and Xianbei were remnants of the Donghu who had fled east. The Xianbei, of the lateral Donghu line, resided to the north of the Wuhuan. The Wuhuan were of the direct Donghu line and got involved in many relations with the Chinese due to their more southern location (around Liaodong). Until 121 BC, the Wuhuan was a tributary of the Xiongnu empire. The Hou Hanshu (Ch. 120) says: "From the time that Modu Shanyu crushed them the Wuhuan became weak. They were kept in constant subjugation to the Xiongnu and were forced to pay annual taxes of cow, horse and sheep skins. If anybody did not pay this tax his wife and children were taken from him."