This is the history of the papacy under three popes, Benedict XV (1914–58), Pius XI (1922–39), and Pius XII (1939–58), who faced the strains imposed on the worldwide Church by total war—two world wars and the Cold War. The totalitarian challenges of fascism, Nazism, and Communism led to unprecedented persecution in the history of Catholicism. Nevertheless, all three popes contributed significantly to the development of the modern papacy. Benedict XV rescued it from diplomatic isolation by his attempts to end the First World War and his humanitarian aid to the war victims. He also promulgated the Code of Canon Law—reinforcing centralized control of the Church from Rome—and renewed Catholic missionary outreach. Pius XI resolved the dispute with Italy over the ‘Roman Question’ and put papal finances on a sounder basis. He also brought about a partial reconciliation between Catholicism and modern science and resisted all three totalitarian dictators, Stalin, Mussolini, and Hitler. Pius XII’s experience of the Second World War was extremely difficult and he was severely criticized for his silences over the Holocaust, though Catholics helped save thousands of Jews and other victims of fascism. During the Cold War he led an anti-Communist crusade in defence of the ‘Church of Silence’ in Eastern Europe and Asia. He also presided over the Church’s response to decolonization. His infallible promulgation of the doctrine of the Assumption in 1950 and rejection of the ecumenical movement marked the high point of papal absolutism and pre-Vatican II Catholicism.