Military history of the Three Kingdoms
By the time of the Three Kingdoms period the Xiongnu had already ceased to be a major power. Their last stand as a steppe empire was in 89 when Dou Xian led an army of 45,000 and decisively defeated them at the Battle of the Altai Mountains. The Xiongnu Empire was replaced by a loose confederation of disorganized Xianbei tribes, who were nonetheless highly aggressive and proved problematic to their southern neighbors. A southern branch of the Xiongnu split off from their northern neighbors in 50 AD and continued to exist as a Han puppet state in Bing Province. However, in 188 the Xiuchuge clan rebelled against their Chanyu, Qiangqu, for sending troops to aid the Han against the rebels Zhang Ju and Zhang Chun. They replaced Qiangqu with his son Yufuluo, who's hold on power was tenuous, and he was ousted over a marquis of the Xubu clan. When the marquis of Xubu died the next year an elderly king became the nominal head of state without the title of Chanyu and the Southern Xiongnu ceased to exist as a coherent entity. In 216 the Xiongnu of the Ordos were settled but the region remained outside the jurisdiction of Cao Wei's administration.
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.