A country of south-central Asia. The region was settled by the Tajik before the 10th century and conquered by Mongols in the 13th century. By the mid-19th century it was divided among several weak khanates. The region was acquired by Russia by 1895 and was a constituent state of the USSR, the Tadzhik Soviet Socialist Republic, from 1929 to 1991, when it declared its independence. Dushanbe is the capital and the largest city.