 While the Vatican was officially neutral during the war , Pius XII maintained links to the German Resistance , used diplomacy to aid the victims of the war and lobby for peace and spoke out against race @-@ based murders and other atrocities . The Reichskonkordat of 1933 and Pius 's leadership of the Catholic Church during World War II remain the subject of controversy — including allegations of public silence and inaction about the fate of the Jews . After the war Pius XII advocated peace and reconciliation , including lenient policies towards Axis and Axis @-@ satellite nations . The Church experienced severe persecution and mass deportations of Catholic clergy in the Eastern Bloc . Pius XII was a staunch opponent of Communism and of the Italian Communist Party . Pius XII explicitly invoked ex cathedra papal infallibility with the dogma of the Assumption of Mary in his 1950 Apostolic constitution Munificentissimus Deus . His magisterium includes almost 1 @,@ 000 addresses and radio broadcasts . His forty @-@ one encyclicals include Mystici corporis , the Church as the Body of Christ ; Mediator Dei on liturgy reform ; and Humani generis on the Church 's positions on theology and evolution . He eliminated the Italian majority in the College of Cardinals in 1946 . 
