As part of the region of
Greater Poland, i.e. the cradle of the Polish state, the area formed part of Poland since its establishment in the 10th century. It was a private church town, administratively located in the Poznań County in the
Poznań Voivodeship in the
Greater Poland Province. In the
Second Partition of Poland, in 1793, it was annexed by
Prussia. After the successful
Greater Poland uprising of 1806, it was regained by Poles and included within the short-lived Polish
Duchy of Warsaw. Following the duchy's dissolution in 1815, it was reannexed by Prussia, and from 1871 it was also part of Germany. The populace was subjected to
Germanisation policies. Following
World War I, in 1918, Poland regained independence and the
Greater Poland uprising against Germany broke out, which goal was to reintegrate the town and region with reborn Poland. The town formed a
company of one hundred insurgents and a platoon of nearly forty, of whom eleven were killed in the uprising. Kostrzyn was reintegrated with Poland.
World War II At the start of
World War II, the town was invaded by Germany on September 10, 1939. On September 16, a detachment of
Einsatzkommando 14 entered Kostrzyn, then gathered all the Polish men at the Market Square and carried out beatings and selection of 100 prisoners, who were eventually sent on foot to a newly established camp in
Swarzędz. That day and in the days that followed, the Germans carried out further murders of local Poles. On October 20, 1939, the Germans carried out a public execution of 28 Poles, including teachers, school principals, merchants, craftsmen, etc. It was one of many massacres of Poles committed by Germany on October 20–23 across the region in attempt to pacify and terrorize the Polish population. In November 1939, the
Hilfspolizei carried out further murders of local Poles. In late 1939, the German police carried out first
expulsions of Poles, mainly families of Poles who were murdered or deported to
concentration camps during the
Intelligenzaktion, plus owners of workshops and better houses. Expelled Poles were deported to the
General Government in the more eastern part of
German-occupied Poland. Most of the Germans responsible for the
crimes against Poles in Kostrzyn fled the town before the approaching
Eastern Front and escaped justice. ==Demographics==