During the Middle Ages, Bashkir tribes inhabited the Southern Urals; they formed part of the Golden Horde, Nogai Horde, and smaller Bashkir unions. The Tsardom of Russia incorporated the area in the late 16th century. However, Russian colonization of the region only began in the 18th century, with the establishment of a system of fortresses and trade posts on the then-Russian border by the in 1734. Many cities of Chelyabinsk Oblast, including the city of Chelyabinsk itself, trace their history back to those forts.