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.
Prehistory of Siberia
Sure statements are possible only since the first millennium BC, when neighbouring literate cultures came into contact with the people of the steppe. In the steppes north of the Black Sea and east of the Caspian Sea, Greek, Assyrian and Persian sources attest to horse nomads, which can be identified as speakers of Iranian languages. The first reports from ancient China of the nomads north of China date from the same period Along with various unidentified groups from Shang and Zhou dynasty texts, the Xiongnu are worthy of mention. Based on personal names and titles transmitted by the Chinese sources, different scholars have attempted to identify the language of the Xiongnu as an early Turkic language, a proto-Mongolic language or a Yeniseian language. At the beginning of the early Middle Ages, the Iranian peoples disappeared and in their place Turkic peoples expanded across the region between the eastern edge of Europe and northeastern Siberia. In the areas to the north of the Asiatic steppes, speakers of Uralic and Palaeo-Siberian languages are suspected to have been settled; in the Middle Ages, Turkic peoples appear here as well, but their prehistoric extent is not clear.