On 1 September 1939 German forces invaded Poland, advancing in a Blitzkrieg (lightning war) to Warsaw and halting at the line agreed beforehand with the Soviet Union in a secret pact of the German-Soviet Non-Aggression Pact of August 23, 1939. On September 3, 1939 Britain, France, Canada, South Africa, Australia and New Zealand declared war on Germany.
The German forces, particularly the SS, terrorised the Polish population, principally the Jews, by subjecting them to humiliation and torture. Synagogues and homes were torched; they were shot, beaten or sent to forced labour. They were falsely accused of causing World War II and compelled to pay reparations through the confiscation of their property and enforced labour.
Within three weeks, German forces crushed Poland and divided it into three geographical entities: the western and northern provinces of the former Polish state, including Poland’s second-largest city, Łodz, were annexed to the Reich; eastern parts were annexed to the Soviet Union; and a section in central Poland was configured into the Generalgouvement — an area into which the Jewish population was concentrated. Consequently, 1.8 million Jews were trapped in the German-occupied sector of Poland and more than a million Polish Jews in the eastern districts of Poland came under Soviet hegemony.
On September 21, 1939, the chief of the Security Police, Reinhard Heydrich, dispatched a Schnellbrief – a directive outlining the means by which the Jews of Poland were to be interned in ghettos, and setting up of Jewish councils, Judenräte, ensuring that all German orders were obeyed.