Suar or Suvar principality was a medieval statelet subject to Volga Bulgaria.
The principality appeared around the 940s CE. The population was a mix of Turkic Suars and local Turkic- and Uralic-speaking tribes such as the Mari. The capital was city of Suar. The ruler of Suar went by the title "Bäk" (cf. Khazar "Bek"; Turkish "Beg".)
In 975 the Suar Duchy was absorbed by Volga Bulgaria. From the 11th-13th century it became a semi-autonomous province of Volga Bulgaria, until the conquest of that state by the Mongols.
(Tatar) "Suar bäklege". Tatar Encyclopedia. Kazan: Tatarstan Republic Academy of Sciences Institution of the Tatar Encyclopaedia. 2002.