Soviets invade Poland

On September 17, when it was clear that the German invasion had succeeded, the Red Army entered the eastern part of Poland in accordance with the secret agreements between Germany and the USSR in the Ribbentrop-Molotov pact. September 21, 1939, it was announced that the Germans would divide the Polish areas that it had occupied into two sectors: One sector was annexed to Germany and became part of the Reich; the other was named the Generalgouvernement and placed under a German civil administration headed by Hans Frank.