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.
Jiangqu
In 51 BCE a pretender to the Xiongnu's throne Huhanye re-established the "heqin" peace and kinship treaty with the Han empire, and fled to China with a fraction of the Xiongnu, partitioning the Xiongnu state into the Northern Xiongnu and Southern Xiongnu, and establishing a new polity allied with China. The Southern Xiongnu retained a title "Chanyu" for their leader, and started a new dynastic line beginning with Huhanye. Huhanye himself belonged to the 8th generation of the Maodun line of the dynastic paternal Luanti tribe, the tribe Qiang ("Kiyan") was a maternal dynastic tribe of the Southern Xiongnu. During the existence of the Southern Xiongnu state, its Xiongnu population greatly varied depending on the events in the steppe, at times it was swelling with numerous Xiongnu tribes fleeing trouble events, and at times it was losing Xiongnu tribes when they returned after return of peaceful times. The Chinese policies also affected the in and out flows. Until the event with Zhang Xiu in 179 CE, the Southern Xiongnu continued electing their Chanyus without explicit Chinese intervention, Jiangqu was the first Southern Xiongnu Chanyu who broke the traditional Xiongnu succession laws, undermining the integrity of the Southern fraction. Tribes that did not want to recognise a non-eligible leader either revolted against him, or left the area under his control.