The ideology of Nazism brought together elements of antisemitism, racial hygiene and eugenics, and combined them with pan-Germanism and territorial expansionism with the goal of obtaining more Lebensraum (living space) for the Germanic people. Immediately after the Nazi seizure of power in Germany, boycotts of German Jews and acts of violence against them became ubiquitous, and legislation was passed excluding them from the civil service and certain professions, including the law.[a] Harassment and economic pressure were used to encourage them to leave Germany; their businesses were denied access to markets, forbidden to advertise in newspapers, and deprived of government contracts.
On 15 September 1935, the Reichstag passed the Nuremberg Laws, prohibiting marriages between Jews and people of Germanic extraction, extramarital relations between Jews and Germans, and the employment of German women under the age of 45 as domestic servants in Jewish households. The Reich Citizenship Law defined as citizens those of "German or kindred blood". Thus Jews and other minorities were stripped of their citizenship. By the start of World War II in 1939, around 250,000 of Germany's 437,000 Jews had emigrated to the United States, Palestine, the United Kingdom, and other countries.
When Germany invaded Poland in September 1939, triggering World War II, Adolf Hitler ordered that the Polish leadership and intelligentsia be destroyed. Approximately 65,000 civilians, viewed as inferior to the Aryan master race, had been killed by the end of 1939. In addition to leaders of Polish society, the Nazis killed Jews, prostitutes, the Roma, and the mentally ill. SS-Obergruppenführer Reinhard Heydrich, then head of the Gestapo, ordered on 21 September 1939 that Polish Jews be rounded up and concentrated into cities with good rail links. Initially the intention was to deport them to points further east, or possibly to Madagascar. Two years later, in June 1941, in an attempt to obtain new territory, Hitler invaded the Soviet Union.