Nomadic empire
The Xiongnu were a confederation of nomadic tribes from Central Asia with a ruling class of unknown origin and other subjugated tribes. They lived on the Mongolian Plateau between the 3rd century BC and the 460s AD, their territories including modern day Mongolia, southern Siberia, western Manchuria, and the modern Chinese provinces of Inner Mongolia, Gansu, and Xinjiang. The Xiongnu was the first unified empire of nomadic peoples. Relations between early Chinese dynasties and the Xiongnu were complicated and included military conflict, exchanges of tribute and trade, and marriage treaties. When Emperor Qin Shihuang drove them away from the south of the Yellow River, he built the famous Great Wall to prevent the Xiongnu from coming back.
Turkic peoples
It has often been suggested that the Xiongnu, mentioned in Han Dynasty records, were Proto-Turkic speakers. Although little is known for certain about the Xiongnu language(s), it seems likely that at least a considerable part of Xiongnu tribes spoke a Turkic language. However, some scholars see a possible connection with the Iranian-speaking Sakas. Some scholars believe they were probably a confederation of various ethnic and linguistic groups. Genetics research in 2003 on skeletons from 2000 year old Xiongnu necropolis in Mongolia found some individuals with DNA sequences also present in some modern-day Turks, suggesting that a Turkish component had emerged in the Xiongnu tribe at the end of the Xiongnu period.