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.
Jin Midi
Jin Midi was born in 134 BC to a royal Xiongnu family. He was the heir apparent to Xiongnu's Prince of Xiutu, one of the major princes under the supreme ruler of the Xiongnu, the "Chanyu" Gunchen. After Gunchen's death in 126 BC, his brother Ichise succeeded him. During this time, the Prince of Xiutu and another major prince, the Prince of Hunye, were responsible for defending Xiongnu's southwestern border with Han Dynasty – modern central and western Gansu.