Xiongnu
Sinologist Edwin Pulleyblank argued that the Xiongnu were part of a Xirong group called Yiqu, who had lived in Shaanbei and had been influenced by China for centuries, before they were driven out by the Qin dynasty. Qin's campaign against the Xiongnu expanded Qin's territory at the expense of the Xiongnu. In 215 BC, Qin Shi Huang sent General Meng Tian to conquer the Xiongnu and drive them from the Ordos Loop, which he did later that year. After the catastrophic defeat at the hands of Meng Tian, the Xiongnu leader Touman was forced to flee far into the Mongolian Plateau. The Qin empire became a threat to the Xiongnu, which ultimately led to the reorganization of the many tribes into a confederacy.In 209 BC, three years before the founding of Han China, the Xiongnu were brought together in a powerful confederation under a new chanyu, Modu Chanyu. This new political unity transformed them into a more formidable state by enabling formation of larger armies and the ability to exercise better strategic coordination. The Xiongnu adopted many of the Chinese agriculture techniques such as slave labor for heavy labor, wore silk like the Chinese, and lived in Chinese-style homes. The reason for creating the confederation remains unclear. Suggestions include the need for a stronger state to deal with the Qin unification of China that resulted in a loss of the Ordos region at the hands of Meng Tian or the political crisis that overtook the Xiongnu in 215 BC when Qin armies evicted them from their pastures on the Yellow River.
Donghu people
The (ca. 109–91 BCE) "Shiji" section on Xiongnu history first records the Donghu during the era of Duke Wen of Jin (r. 697–628 BCE) and Duke Mu of Qin (r. ca. 659–621 BCE).At this time Qin and Jin were the most powerful states in China. Duke Wen of Jin expelled the Di barbarians and drove them into the region west of the Yellow River between the Yun and Luo rivers; there they were known as the Red Di and the White Di. Shortly afterwards, Duke Mu of Qin, having obtained the services of You Yu, succeeded in getting the eight barbarian tribes of the west to submit to his authority.
Thus at this time there lived in the region west of Long the Mianzhu, the Hunrong, and the Diyuan tribes. North of Mts. Qi and Liang and the Jing and Qi rivers lived the Yiqu, Dali, Wuzhi, and Quyuan tribes. North of Jin were the Linhu (Forest Barbarians) and the Loufan, while north of Yan lived the Donghu (Eastern Barbarians) and Shanrong (Mountain Barbarians), each of them with their own chieftains. From time to time they would have gatherings of a hundred or so men, but no one tribe was capable of unifying the others under a single rule.