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.
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.