children was curtailed to a few years of elementary education, as outlined by Himmler's May 1940 memorandum: "The sole goal of this schooling is to teach them simple arithmetic, nothing above the number 500; writing one's name; and the doctrine that it is divine law to obey the Germans. ... I do not think that reading is desirable". Extermination of elites The extermination of the Polish elite was the first stage of the Nazis' plan to destroy the Polish nation and its culture. The disappearance of the Poles' leadership was seen as necessary to the establishment of the Germans as the Poles' sole leaders. Proscription lists (Sonderfahndungsbuch Polen), prepared before the war started, identified more than 61,000 members of the Polish elite and intelligentsia leaders who were deemed unfriendly to Germany. Already during the 1939 German invasion, dedicated units of SS and police (the Einsatzgruppen) were tasked with arresting or outright killing of those resisting the Germans. They were aided by some regular German army units and "self-defense" forces composed of members of German minority in Poland, the Volksdeutsche. The Nazi regime's policy of murdering or suppressing the ethnic Polish elites was known as Operation Tannenberg. This included not only those resisting actively, but also those simply capable of doing so by the virtue of their social status. As a result, tens of thousands of people found "guilty" of being educated (members of the intelligentsia, from clergymen to government officials, doctors, teachers and journalists) or wealthy (landowners, business owners, and so on) were either executed on spot, sometimes in mass executions, or imprisoned, some destined for the concentration camps. Some of the mass executions were reprisal actions for actions of the Polish resistance, with German officials adhering to the collective guilt principle and holding entire communities responsible for the actions of unidentified perpetrators. One of the most infamous German operations was the Außerordentliche Befriedungsaktion (AB-Aktion in short, German for Special Pacification), a German campaign during World War II aimed at Polish leaders and the intelligentsia, including many university professors, teachers and priests. In the spring and summer of 1940, more than 30,000 Poles were arrested by the German authorities of German-occupied Poland. Several thousands were executed outside Warsaw, in the Kampinos forest near Palmiry, and inside the city at the Pawiak prison. Most of the remainder were sent to various German concentration camps. Mass arrests and shootings of Polish intellectuals