In 215 BC, Qin Shi Huang ordered General Meng Tian to set out against the Xiongnu tribes in the Ordos region, and establish a frontier region at the loop of the Yellow River.[1] Believing that the Xiongnu were a possible threat, the emperor launched a preemptive strike against the Xiongnu with the intention to expand his empire.[1]
| Qin's campaign against the Xiongnu | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Map of the Ordos region | |||||||||
| |||||||||
| Belligerents | |||||||||
| Qin dynasty | Xiongnu | ||||||||
| Commanders and leaders | |||||||||
| Meng Tian | Touman | ||||||||
| Strength | |||||||||
| Reported as 100,000 or 300,000 troops[1][2] | — | ||||||||
In 215 BC, Meng Tian succeeded in defeating the Xiongnu, driving them from the Ordos and seizing their homeland.[3] After the catastrophic defeat at the hands of Meng Tian, the Xiongnu leader Touman was forced to flee far north into the Mongolian Plateau.[4]
Following the victory against the nomads, Meng Tian was instructed to secure the frontier with a line of fortifications, which would become known as the Great Wall of China.[5] Crown Prince Fusu and General Meng Tian were stationed at a garrison in Suide and soon began with the construction of the walled defenses, which would be connected with the old walls from the Qin, Yan, and Zhao states.[6]
As a result of the northward expansion, the threat that the Qin empire posed to the Xiongnu ultimately led to the reorganization of the many different Xiongnu tribes as they united into a confederacy against the unified Chinese state.[7]