History of Mongolia
Although the Xiongnu finally had been split into two parts in AD 48, the Xianbei (or Hsien-pei in Wade–Giles) had moved (apparently from the east) into the region vacated by the Xiongnu. The Xianbei were the northern branch of the Donghu (or Tung Hu, the Eastern Hu), a proto-Mongol group mentioned in Chinese histories as existing as early as the 4th century BC. The language of the Donghu is believed to be proto-Mongolic to modern scholars. The Donghu were among the first peoples conquered by the Xiongnu. Once the Xiongnu state weakened, however, the Donghu rebelled. By the 1st century AD, two major subdivisions of the Donghu had developed: the proto-Mongolic Xianbei in the north and the Wuhuan in the south.
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.