Tatar (; Tatar; Middle Mongol: ) was one of the five major tribal confederations (khanlig) in the Mongolian Plateau in the 12th century.
The name "Tatar" was possibly first transliterated in the Book of Song as 大檀 Dàtán (MC: *daH-dan) and 檀檀 Tántán (MC: *dan-dan) which the book's compilers stated to be other names of the Rourans; Book of Song and Book of Liang connected Rourans to the earlier Xiongnu while the Book of Wei traced the Rouran's origins back to the Donghu, who were of Proto-Mongolic origin.
Xu proposed that "the main body of the Rouran were of Xiongnu origin" and Rourans' descendants, namely Da Shiwei (aka Tatars), contained Turkic-speaking Xiongnu elements to a great extent. Even so, the language of the Xiongnu is still unknown, and Chinese historians routinely ascribed Xiongnu origins to various nomadic groups, yet such ascriptions do not necessarily indicate the subjects' exact origins: for examples, Xiongnu ancestry was ascribed to Turkic-speaking Göktürks and Tiele as well as Para-Mongolic-speaking Kumo Xi and Khitans.
The first precise transcription of the Tatar ethnonym was written in Turkic on the Orkhon inscriptions, specifically, the Kul Tigin (CE 732) and Bilge Khagan (CE 735) monuments as 𐰆𐱃𐰔⁚𐱃𐱃𐰺⁚𐰉𐰆𐰑𐰣 and 𐱃𐰸𐰔⁚𐱃𐱃𐰺 referring to the Tatar confederation. In historiography, the Proto-Mongolic Shiwei tribes are usually identified with Dada or Thirty Tatars, whereas the sources often refer to the actual Tatars as Nine Tatars, which nine large clans are traditionally distinguished.
Tatars from the Orkhon inscriptions (including Nine Tatars), according to orientalist and archaeologist Leonid Kyzlasov, they were Turkic-speaking. According to Britannica, they might be related to Kipchak and/or Cuman peoples. On the other hand, according to sinologist Paul Pelliot, Tatars from the Orkhon inscriptions were Mongolian-speaking. Tatars were proposed to dwell in Northeastern Mongolia and around Lake Baikal, or between Manchuria and Lake Baikal.
Toquz-Tatars and Otuz-Tatars were sometimes proposed to be Mongolic speakers.