The thesis examines how Catholics in West Germany participated in public discourses on war and peace during the major period of the Cold War (1957-1983). As a result, the study provides new insights into the transformations of religion and society after 1945. First, it reveals a fundamental and lasting re-codification of the political culture of Catholics in West Germany. While most Catholics had primarily focussed on the limitation of war, their attitudes changed towards positive and dynamic peace concepts during the 1960s and 1970s. At the same time, an increasing plurality of Catholic opinions was recognizable. Second, this re-codification of Catholic concepts of peace and war came closely along with a more general re-structuring of the Catholic discourse during the sample period. Part of this process was a general conflict about Catholic self-perception. Against this background, individualistic and pluralistic ideas stood against the continuing hierarchical conception of the Church. The re-structuring included institutional changes which corresponded to the aforementioned tensions. In addition, the process imposed a new understanding of the “Catholic public sphere”. Third, these interior transformations were deeply connected to a re-definition of the religious field. On the one hand, this process included a continuous involvement with other religious actors and, in the West German case, Protestants especially. On the other hand, discourses on peace and war easily exposed the boundaries between the religious and political spheres, especially as the power of public peace movements was growing. Against this background, the study reveals a politicisation of Catholic discourses during the 1960s and 1970s followed by a withdrawal into the religious sphere during the 1980s, a strongly interdenominational decade. Finally, the participation of West German Catholics in public discourses on war and peace contributed the pacification of the Cold War in the long run. Catholics promoted a reduction in distrust between Western and Eastern countries by campaigning for reconciliation. At the same time, they increased their own commitment in development cooperation. Lastly, the positive peace concept decisively delegitimized an oversimplified, military security policy.