Bielsk Podlaski has a long and rich history, dating back to the 12th century, when this area of Poland belonged to Kievan Rus'. The gord of Bielsk was probably founded by Ruthenian dukes, and its existence was first mentioned in 1253, in the so-called Hypatian Codex. In 1273, Bielsk was captured by Lithuanian duke Traidenis, and in the early 14th century, whole province of Podlasie became annexed by the Grand Duchy of Lithuania. The region was subject to Teutonic Knights raids, which took place in 1346 and 1379.