Soviet invasion of Poland – 17 September 1939

On early morning 17 September 1939 the Soviet Union invaded Poland without a formal declaration of war. At this time twenty five Polish divisions were still fighting the Germans. The joint German-Soviet invasion of Poland was secretly agreed to in the Molotov-Ribbentrop Pact, signed on 23 August1939 which split the then Europe into two spheres of influence controlled by two totalitarian systems of the Nazi Germany and of the communist Soviet Union. The Soviet government used the German invasion of Poland as a pretext to violate the non-aggression treaty, announced the Polish state as non-existent and claimed that it entered Polish territory to defend Ukrainian and Belarusian people.

“It became apparent that all that was needed was an initial attack of the German Army and, after that, the attack of the Soviet Army; in order to leave nothing of Poland, this monstrous bastard of the Treaty of Versailles …”
(from the speech of Vyacheslav Molotov, Soviet Prime Minister, to the Supreme Soviet on September 31, 1939 about the German-Soviet invasion of Poland).

At the end of September 1939 the division of Poland was confirmed by German–Soviet Treaty of Friendship, Cooperation and Demarcation which included a correction of the borders first drawn in the secret clause of the Ribbentop-Molotov Pact.

For our Nation it meant “the fourth partition of Poland”. As a result of the Soviet Russia invasion about three-fifth of the Polish territory was occupied by the Soviet Russia. Hundreds of thousands of Polish citizens were deported to Siberia, Kazakhstan and other remote parts of the Soviet Union.

In the Spring of 1940, on the basis of Stalin’s decision thousands of Polish officers and soldiers as well as political prisoners, representatives of educated professional elites were murdered in mass killings, in places like Katyn.