The Nazi authorities set up the Reichsgau Wartheland (Reich Shire Warta Land) as an administrative unit in late October and early November 1939. This signalled the persecution – and at times, even the extermination – of the Polish population. The entire occupation period was associated with increasing hardships. A curfew was imposed and all residents aged 14 and over were called up for forced labour, both in Wielkopolska and in the heart of the Reich. German was compulsory in offices and schools and the Polish education system was all but wound up.

Intellectuals, patriots, Polish nationalists and authority figures were the first to be exterminated. Special groups of the German Security Police made arrests on the basis of lists drawn up before the war had even begun. Their prisoners were generally held like hostages. Some of these people were killed in October and November 1939 in a massive wave of public executions carried out all over Wielkopolska, most frequently in city marketplaces.

Fort VII in Poznań was set up as a penal and interrogation camp as early as October. The Gestapo detained and executed prisoners. A separate camp was later set up in Żabikowo, near Poznań. The conditions resembled those of an extermination camp. Prisoners were subjected to the death penalty and Poles were “re-educated”. The Chełmno extermination camp in Chełmno nad Nerem (Koło County) was mainly dedicated to exterminating the Jewish population. Families displaced from Poznań were placed in a camp in Główna and then transported by train to the General Government, most frequently in the vicinity of Kielce and Ostrowiec Świętokrzyski.