A semiautonomous region of west-central Russia. The site of a powerful Bulgar state after the 8th century, the region was conquered by Mongols in the 13th century and by Moscow in 1552. The Tatar Autonomous Soviet Socialist Republic was established in 1920, and in 1991 it declared its independence. Along with Chechnya, the republic was not a signatory to the 1992 treaty that created the Russian Federation, but it did join later, in 1994.