Xiongnu: A multi-ethnic nomadic grouping from Central Asia, which existed between about 300 B.C. and 450 A.D.
The Xiongnu were based in what is now Mongolia, and frequently raided south into China. They were such a threat that the first Qin Dynasty emperor, Qin Shi Huang, ordered the construction of huge fortifications along the northern border of China - fortifications that later were expanded into the Great Wall of China.
Scholars have long debated the ethnic identity of the Xiongnu: Were they a Turkic people, Mongolian, Persian, or some mixture? In any case, they were a warrior people to be reckoned with.
One ancient Chinese scholar, Sima Qian, wrote in the "Records of the Grand Historian" that the last emperor of the Xia Dynasty, who ruled sometime around 1600 B.C., was a Xiongnu man. However, it is impossible to prove or disprove this claim.
Be that as it may, by 129 B.C., the new Han Dynasty decided to declare war against the troublesome Xiongnu. (The Han sought to re-establish trade along the Silk Road to the west - and the Xiongnu made this a difficult task.)
The balance of power between the two sides shifted over the next few centuries, but the Northern Xiongnu were driven out of Mongolia after the Battle of Ikh Bayan (89 A.D.), while the Southern Xiongnu were absorbed into Han China.
Historians believe that the Northern Xiongnu continued west until they reached Europe under a new leader, Attila, and a new name, the Huns.
"DNA evidence from Egyin Gol indicates that at least some of the Xiong-nu were ethnically Turkic, and that they were of mixed Asian and European descent."