Xiongnu
Full-scale war broke out in autumn 129 BC, when 40,000 Chinese cavalry made a surprise attack on the Xiongnu at the border markets. In 127 BC, the Han general Wei Qing retook the Ordos. In 121 BC, the Xiongnu suffered another setback when Huo Qubing led a force of light cavalry westward out of Longxi and within six days fought his way through five Xiongnu kingdoms. The Xiongnu Hunye king was forced to surrender with 40,000 men. In 119 BC both Huo and Wei, each leading 50,000 cavalrymen and 100,000 footsoldiers (in order to keep up with the mobility of the Xiongnu, many of the non-cavalry Han soldiers were mobile infantrymen who traveled on horseback but fought on foot), and advancing along different routes, forced the "chanyu" and his court to flee north of the Gobi Desert. Major logistical difficulties limited the duration and long-term continuation of these campaigns. According to the analysis of Yan You (嚴尤), the difficulties were twofold. Firstly there was the problem of supplying food across long distances. Secondly, the weather in the northern Xiongnu lands was difficult for Han soldiers, who could never carry enough fuel. According to official reports, the Xiongnu lost 80,000 to 90,000 men, and out of the 140,000 horses the Han forces had brought into the desert, fewer than 30,000 returned to China.
Cong (surname)
The Congs are originally of Xiongnu origin. They trace their ancestry to King Xiutu of the Xiongnu. In 121 BC, Xiongnu King Hunxie killed King Xiutu when Xiutu refused to surrender to the Chinese with Hunxie. The fourteen-year-old Crown Prince Midi was taken to China and raised as a stable hand. One day, when Emperor Wu of Han was inspecting the horses with his wives, all the servants were mesmerized by the royal entourage, except for Midi. Emperor Wu of Han took favor of the prince and granted him the Chinese surname Jin, meaning gold, because the prince used to make sacrifices with golden statues as a part of the Xiongnu rituals.