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
After their previous overlords, the Yuezhi, migrated into Central Asia during the 2nd century BC, the Xiongnu became a dominant power on the steppes of north-east Central Asia, centred on an area known later as Mongolia. The Xiongnu were also active in areas now part of Siberia, Inner Mongolia, Gansu and Xinjiang. Their relations with adjacent Chinese dynasties to the south east were complex, with repeated periods of conflict and intrigue, alternating with exchanges of tribute, trade, and marriage treaties.