Ordos Plateau
In Chinese accounts, the Xiongnu first appear at Ordos in the "Yizhoushu" and "Shanhaijing" during the Warring States period before it was occupied by Qin and Zhao. It is generally thought to be their homeland, however when exactly they came to occupy the region is unclear, and it might have been much earlier than traditionally thought, as suggested by archaeological finds. As the Xiongnu expanded southward into Yuezhi territory around 160 BC under their leader Modun, the Yuezhi in turn defeated the Sakas (Scythians) and pushed them away at the Issyk Kul. It is thought the Xiongnu also occupied the Ordos area during the same period, when they came in direct contact with the Chinese. From there, the Xiongnu conducted numerous devastating raids into Chinese territory (167, 158, 142, 129 BC). The Han Dynasty started to fight the Xiongnu in the 2nd century BC under emperor Han Wudi, and colonized the area of the Ordos under Shuofang commandery in 127 BC. Prior to the campaign, there were already commanderies established earlier by Qin and Zhao until they were overrun by the Xiongnu in 209 BC.
Economic history of China before 1912
In 304, there was a massive uprising of barbarian clans that were under Chinese control. Following several years of civil war between the various princes of the Jin dynasty, the Xiongnu, led by Liu Yuan, revolted and declared their independence from China. Several other groups under Chinese control subsequently revolted, including the Jie, Qiang, Di, and Xianbei. These groups became collectively known as the Wu Hu, committing genocide against Han Chinese in the Yellow River valley. The collapse of the Jin Empire quickly followed these revolts. The Wu Hu invasion caused large-scale depopulation and the market economy that developed during the Qin, Han, Wei and Jin to decline rapidly, allowing the feudal manorial economy returned to prominence. Large manorial estates were self-sufficient and isolated from the wider market. These estates were self-contained economies that practised agriculture, herding, forestry, fishing, and the production of handicraft goods. Exchange was no longer carried out through money, but barter. Following the economic revival after the unification of the Sui, the manorial economy again declined.