The miners in the Ruhr region were divided by ethnicity (with Germans and Poles) and religion (Protestants and Catholics). Mobility in and out of the mining camps to nearby industrial areas was high. The miners split into several unions, with an affiliation to a political party. As a result, the socialist union (affiliated with the Social Democratic Party) competed with Catholic and Communist unions until 1933, when the Nazis took over all of them. After 1945 the socialists came to the fore.