The Invasion of Poland in 1939 was a military campaign in which Nazi Germany and the Soviet Union invaded Poland. The invasion marked the beginning of World War II, and it resulted in the occupation of Poland by the two powers. The invasion was a result of the signing of the Molotov–
The invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939, was a joint attack on the Republic of Poland by Nazi Germany, the Slovak Republic, and the Soviet Union, which marked the beginning of World War II. The German invasion was preceded by the Danzig crisis and began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union, and one day after the Supreme Soviet of the Soviet Union had approved the pact. The Soviets invaded Poland on 17 September. The campaign ended on 6 October with Germany and the Soviet Union dividing the whole of Poland under the terms of the German–Soviet Frontier Treaty.