In April 1940, Rudolph Höss, who become the first commandant, identified the Silesian town of Oswiecim as a possible site for a concentration camp. The function of the camp was initially to intimidate Poles and prevent resistance to German rule. It was also perceived as a cornerstone of the policy to re-colonize Upper Silesia, which had once been a German region, with 'pure Aryans'. On April 27th, Himmler ordered construction of the camp.
Sprawozdanie 6/42 was sent to Polish officials in London by courier and had reached them by 12 November 1942, when it was translated into English and added to another report, "Report on Conditions in Poland". Dated 27 November, this was forwarded to the Polish Embassy in the United States. On 10 December 1942, the Polish Foreign Affairs Minister, Edward Raczyński, addressed the fledgling United Nations on the killings; the address was distributed with the title The Mass Extermination of Jews in German Occupied Poland. He told them about the use of poison gas; about Treblinka, Bełżec and Sobibor; that the Polish underground had referred to them as extermination camps; and that tens of thousands of Jews had been killed in Bełżec in March and April 1942. One in three Jews in Poland were already dead, he estimated, from a population of 3,130,000. Raczyński's address was covered by the New York Times and The Times of London. Winston Churchill received it, and Anthony Eden presented it to the British cabinet. On 17 December 1942, 11 Allies issued the Joint Declaration by Members of the United Nations condemning the "bestial policy of cold-blooded extermination".
Throughout the spring and summer of 1940, the German army expanded Hitler’s empire in Europe, conquering Denmark, Norway, the Netherlands, Belgium, Luxembourg and France. Beginning in 1941, Jews from all over the continent, as well as hundreds of thousands of European Gypsies, were transported to the Polish ghettoes. The German invasion of the Soviet Union in June 1941 marked a new level of brutality in warfare. Mobile killing units called Einsatzgruppenwould murder more than 500,000 Soviet Jews and others (usually by shooting) over the course of the German occupation.
German operational theories were revised after the First World War. The Treaty of Versailles limited the Reichswehr to a maximum of 100,000 men, making impossible the deployment of mass armies. The German General Staff was abolished by the treaty but continued covertly as the Truppenamt (Troop Office), disguised as an administrative body. Committees of veteran staff officers were formed within the Truppenamt to evaluate 57 issues of the war. By the time of the Second World War, their reports had led to doctrinal and training publications, including H. Dv. 487, Führung und Gefecht der verbundenen Waffen (Command and Battle of the Combined Arms), known as das Fug (1921–23) and Truppenführung (1933–34), containing standard procedures for combined-arms warfare. The Reichswehr was influenced by its analysis of pre-war German military thought, in particular infiltration tactics, which at the end of the war had seen some breakthroughs on the Western Front and the manoeuvre warfare which dominated the Eastern Front.
Peter Hayes (How Was It Possible? A Holocaust Reader, 2015): "The Holocaust, the Nazi attempt to eradicate the Jews of Europe, has come to be regarded as the emblematic event of Twentieth Century ... Hitler's ideology depicted the Jews as uniquely dangerous to Germany and therefore uniquely destined to disappear completely from the Reich and all territories subordinate to it. The threat posted by supposedly corrupting but generally powerless Sinti and Roma was far less, and therefore addressed inconsistently in the Nazi realm. Gay men were defined as a problem only if they were German or having sex with Germans or having sex with Germans and considered 'curable' in most cases. ... Germany's murderous intent toward the handicapped inhabitants of European mental institutions ... was more comprehensive ... but here, too, implementation was uneven and life-saving exceptions permitted, especially in Western Europe. Not only were some Slavs—Slovaks, Croats, Bulgarians, some Ukrainians—allotted a favored place in Hitler's New Order, but the fate of most of the other Slavs the Nazis derided as sub-humans ... consisted of enslavement and gradual attrition, not the prompt massacre meted out to the Jews after 1941."
When Hitler came to power legally on January 30, 1933, as the head of a coalition government, his first objective was to consolidate power and to eliminate political opposition. The assault against the Jews began on April 1 with a boycott of Jewish businesses. A week later the Nazis dismissed Jews from the civil service, and by the end of the month the participation of Jews in German schools was restricted by a quota. On May 10 thousands of Nazi students, together with many professors, stormed university libraries and bookstores in 30 cities throughout Germany to remove tens of thousands of books written by non-Aryans and those opposed to Nazi ideology. The books were tossed into bonfires in an effort to cleanse German culture of “un-Germanic” writings. A century earlier Heinrich Heine—a German poet of Jewish origin—had said, “Where one burns books, one will, in the end, burn people.” In Nazi Germany the time between the burning of Jewish books and the burning of Jews was eight years.
During the interwar period, aircraft and tank technologies matured and were combined with systematic application of the traditional German tactic of Bewegungskrieg (maneuver warfare), deep penetrations and the bypassing of enemy strong points to encircle and destroy enemy forces in a Kesselschlacht (cauldron battle). During the Invasion of Poland, Western journalists adopted the term blitzkrieg to describe this form of armoured warfare. The term had appeared in 1935, in a German military periodical Deutsche Wehr (German Defence), in connection to quick or lightning warfare. German manoeuvre operations were successful in the campaigns of 1939–1941 and by 1940 the term blitzkrieg was extensively used in Western media. Blitzkrieg operations capitalized on surprise penetrations (e.g., the penetration of the Ardennes forest region), general enemy unreadiness and their inability to match the pace of the German attack. During the Battle of France, the French made attempts to re-form defensive lines along rivers but were frustrated when German forces arrived first and pressed on.
After some time off to recover in Zwittau, Schindler was promoted to second in command of his Abwehr unit and relocated with his wife to Ostrava, on the Czech-Polish border, in January 1939. He was involved in espionage in the months leading up to Hitler's seizure of the remainder of Czechoslovakia in March. Emilie helped him with paperwork, processing and hiding secret documents in their apartment for the Abwehr office. As Schindler frequently travelled to Poland on business, he and his 25 agents were in a position to collect information about Polish military activities and railways for the planned invasion of Poland. One assignment called for his unit to monitor and provide information about the railway line and tunnel in the Jablunkov Pass, deemed critical for the movement of German troops. Schindler continued to work for the Abwehr until as late as fall 1940, when he was sent to Turkey to investigate corruption among the Abwehr officers assigned to the German embassy there.