In my doctoral project, I aim to use the recently made accessible sources from the Vatican archives and documents from archives in Bosnia and Albania to pursue the question of how Pope Pius XII dealt with the complex multi-confessional post-war societies of Yugoslavia, and here especially Bosnia, and Albania against the backdrop of regional, transnational and international political conditions and challenges. The inter-religious contacts that the pontificate maintained in the Balkans and the themes and motives that framed these contacts are the focus of my research. In terms of both ecclesiastical and regional history, in many scholarly works, the period of political opening and inter-religious or ecumenical dialogue of the Catholic Church only begins with the death of Pius XII. The inter-confessional contacts of the Holy See in the immediate postwar period, on the other hand, have so far hardly been the subject of academic discussion. My research therefore not only hopes to provide new insights into the inter-religious relations in Balkan multi-confessional societies at the time of communism, and thus make an important contribution to the history of Southeastern Europe in the post-war period. By analyzing interconfessional contacts between the Vatican and other religious communities during the pontificate of Pius XII, the research project also tries to answer broader questions regarding the history of the catholic church after the second World War.