However, with power secured in Germany, Hitler quickly broke this promise.[35] He divided the Lutheran Church (Germany's main Protestant denomination) and instigated a brutal persecution of the Jehovah's Witnesses.[36] He dishonoured a Concordat signed with the Vatican and permitted a persecution of the Catholic Church in Germany.[37] A special Priests Barracks was established at Dachau Concentration Camp for clergy who had opposed the Hitler regime – its occupants were mainly Polish Catholic clergy.