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.
Xiongnu
Ancient China often came in contact with the Xianyun and the Xirong nomadic peoples. In later Chinese historiography, some groups of these peoples were believed to be the possible progenitors of the Xiongnu people. These nomadic people often had repeated military confrontations with the Shang and especially the Zhou, who often conquered and enslaved the nomads in an expansion drift. During the Warring States period, the armies from the Qin, Zhao, and Yan states were encroaching and conquering various nomadic territories that were inhabited by the Xiongnu and other Hu peoples.