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.
History of Central Asia
In the 2nd and 1st millennia BC, a series of large and powerful states developed on the southern periphery of Central Asia (the Ancient Near East). These empires launched several attempts to conquer the steppe people, but met with only mixed success. The Median Empire and Achaemenid Empire both ruled parts of Central Asia. The Xiongnu Empire (209 BC-93 (156) AD) may be seen as the first central Asian empire which set an example for later Göktürk and Mongol empires. Xiongnu's ancestor Xianyu tribe founded Zhongshan state (c. 6th century BC – c. 296 BC) in Hebei province, China. The title chanyu was used by the Xiongnu rulers before Modun Chanyu so it is possible that statehood history of the Xiongnu began long before Modun's rule.