In its narrowest definition, Kulturkampf was Otto Von Bismark’s struggle with the Roman Catholic Church in the early 1870s. In actuality, it had an enormous effect on the Polish provinces of Prussia beyond the conflict between church and state.
Most Poles were Roman Catholics. Kulturkampf affected every aspect of their lives.
In 1872, a decree demanded that the use of the German language was compulsory in all state schools. The Polish language was banned - even as a foreign language.  In all courts and public offices, down to the local post office, business was conducted only in the German language
This was a key move in the process of Germanification of the Prussian Poland. German citizens were encouraged to migrate to Poland, and were given priority when acquiring property and in hiring.
It is no surprise to me that my ancestors chose to emigrate to the United States.
God’s Playground – Norman Davies
Gold and Iron – Fritz Stern