Seventeen days after the German invasion of Poland in 1939, which marked the beginning of the Second World War, the Soviet Union invaded the eastern regions of Poland (known as the Kresy) and annexed territories totaling 201,015 square kilometres (77,612 sq mi) with a population of 13,299,000. Inhabitants besides ethnic Poles included Czechs, Lithuanians, Belarusians, Ukrainians Jews, and other minority groups.