Discrimination against Jews began immediately after the Nazi seizure of power on 30 January 1933. Violence and economic pressure were used by the Nazi regime to encourage Jews to voluntarily leave the country. After the invasion of Poland in September 1939, the extermination of European Jewry began, and the killings continued and accelerated after the invasion of the Soviet Union in June 1941. On 31 July 1941, Hermann Göring gave written authorization to Heydrich to prepare and submit a plan for a "total solution of the Jewish question" in territories under German control and to coordinate the participation of all involved government organisations. At the Wannsee Conference, Heydrich emphasised that once the deportation process was complete, the fate of the deportees would become an internal matter under the purview of the SS. A secondary goal was to arrive at a definition of who was Jewish.