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.
Xiongnu
Chinese sources link the Tiele people and Ashina to the Xiongnu, not all Turkic peoples. According to the "Book of Zhou" and the "History of the Northern Dynasties", the Ashina clan was a component of the Xiongnu confederation, but this connection is disputed, and according to the "Book of Sui" and the "Tongdian", they were "mixed nomads" () from Pingliang. The Ashina and Tiele may have been separate ethnic groups who mixed with the Xiongnu. Indeed, Chinese sources link many nomadic peoples ("hu"; see "Wu Hu") on their northern borders to the Xiongnu, just as Greco-Roman historiographers called Avars and Huns "Scythians". The Greek cognate of "Tourkia" () was used by the Byzantine emperor and scholar Constantine VII Porphyrogenitus in his book "De Administrando Imperio", though in his use, "Turks" always referred to Magyars. Such archaizing was a common literary "topos", and implied similar geographic origins and nomadic lifestyle but not direct filiation. Some Uyghurs claimed descent from the Xiongnu (according to Chinese history "Weishu", the founder of the Uyghur Khaganate was descended from a Xiongnu ruler), but many contemporary scholars do not consider the modern Uyghurs to be of direct linear descent from the old Uyghur Khaganate because modern Uyghur language and Old Uyghur languages are different. Rather, they consider them to be descendants of a number of people, one of them the ancient Uyghurs.