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.
Han–Xiongnu War
In 73 AD, General Dou Gu and his army departed from Jiuquan and advanced towards the Northern Xiongnu, defeating the Northern Xiongnu and pursuing them as far as Lake Barkol before establishing a garrison at Hami. In 74 AD, Dou Gu retook Turfan from the Xiongnu. The Han campaigns resulted in the retreat of the Northern Xiongnu to Dzungaria, while Ban Chao was threatening and bringing the city-states at the Tarim Basin to submission under the Han empire once again. In 74 AD, the King of Jushi submitted to the Han forces under General Dou Gu as the Xiongnu were unable to engage the Han forces.