The Czechs and Poles collaborated on resisting Germanization movements .
This collaboration ceased after World War I. In 1920 the region of Zaolzie was incorporated into Czechoslovakia after an armed conflict between Poland and Czechoslovakia .
The Czechs and Poles collaborated on resisting Germanization movements , but this collaboration ceased after World War I. In 1920 the region of Zaolzie was incorporated into Czechoslovakia after an armed conflict between Poland and Czechoslovakia .