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 migration
The population ancestral to the Turks is thought to have included the Xiongnu of Mongolia or along the upper Yenisei in Siberia (the area of the contemporary Tuvan language), known from historical sources. The Han chronicle of the Xiongnu, included in the "Records of the Grand Historian" of the second century BCE, traces a legendary history of them back a thousand years before the Han to a legendary ancestor, Chunwei, a supposed descendant of the Chinese rulers of the Xia dynasty (c. 2070 – c. 1600 BCE). Chunwei lived among the "Mountain Barbarians" Xianyun or Hunzhu. Xianyun and Hunzhu's names may connect them to the Turkic people, who later were said to have been iron-workers and to have kept a national shrine in a mountain cave in Mongolia.