World War II broke out when Germany (as well as Russia) invaded Poland on September 1, 1939. The German blitzkrieg, or lightning war, strategy was revealed: 60 divisions of 1.5 million German soldiers invaded, with support from 2,000 tanks, 900 bombers, and 400 fighter planes. The world was shocked by the rapid progress of German forces through Poland, as well as by the ruthlessness of the German advance; hundreds of thousands of Polish soldiers and civilians were killed or injured. While Poland managed to mobilize around 1 million troops, they had no tanks, outdated weaponry, and only a very small air force. As a result, Poland was overwhelmed by the German invasion and defeated in October 1939. Poland was partitioned between Germany and the Soviet Union.

Germany’s control of Poland allowed them to institute their program of state-sanctioned antisemitism. This included banning Jewish people from schools, shops, and workplaces, and redistributing Jewish populations from their existing housing into crowded, unsanitary ghettos. This process is described in Yellow Star, which is set in the Lodz Ghetto (Hughs, Thomas A. and Rhoyde-Smith, John Graham. “WWII.” Britannica, 1998).