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.
History of Tuva
The Xiongnu ruled over the area of Tuva prior to 200 AD. The identity of the ethnic core of Xiongnu has been a subject of varied hypotheses and proposals by scholars including Mongolic and Turkic. At this time a people known to the Chinese as Dingling inhabited the region. The Chinese recorded the existence of a tribe of Dingling origin named "Dubo" in the eastern Sayans. This name is recognized as being associated with the Tuvan people and is the earliest written record of them. The Xianbei defeated the Xiongnu and they in turn were defeated by the Rouran. From around the end of the 6th century, the Göktürks held dominion over Tuva up until the 8th century when the Uyghurs took over.