During the German Occupation of Poland (1939–1945), the Nazis brutally suppressed the Catholic Church in Poland, most severely in German-occupied areas of Poland. Thousands of churches and monasteries were systematically closed, seized or destroyed. As a result, many works of religious art and objects were permanently lost.

The occupation of Poland by Nazi Germany and the Soviet Union during World War II (1939–1945) began with the Invasion of Poland in September 1939, and it was formally concluded with the defeat of Germany by the Allies in May 1945. Throughout the entire course of the occupation, the territory of Poland was divided between Nazi Germany and the Soviet Union (USSR), both of which intended to eradicate Poland's culture and subjugate its people. In the summer-autumn of 1941, the lands which were annexed by the Soviets were overrun by Germany in the course of the initially successful German attack on the USSR. After a few years of fighting, the Red Army drove the German forces out of the USSR and crossed into Poland from the rest of Central and Eastern Europe.