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.
Ordos culture
In Chinese accounts, the Xiongnu first appear at Ordos in the "Yi Zhou Shu" and "Classic of Mountains and Seas" during the Warring States period before it was occupied by the states of Qin and Zhao. It is generally thought to be their homeland; however, when exactly they came to occupy the region is unclear and archaeological finds suggest it might have been much earlier than traditionally thought.