He was mayor during the postwar British occupation. He established a good working relationship with the British military authorities, using them to neutralize the workers' and soldiers' council that had become an alternative base of power for the city's left wing. During the Weimar Republic, he was president of the Prussian State Council () from 1921–33, which was the representation of the provinces of Prussia in its legislature. A major debate had occurred within the "Zentrum" since 1906 regarding the question of whether the "Zentrum" should "leave the tower" (i.e. allow Protestants to join to become a multi-faith party) or "stay in the tower" (i.e. continue to be a Catholic-only party). Adenauer was one of the leading advocates of "leaving the tower", which led to a dramatic clash between him and Cardinal Michael von Faulhaber at the 1922 "Katholikentag", where the Cardinal publicly admonished Adenauer for wanting to take the "Zentrum" "out of the tower".