Pope Pius XII, often called the 'Peace Pope,' spanned his controversial pontificate during World War II and the postwar period, during which he was accused of silence about the Holocaust despite reports of his secret actions to save Jews and combat Nazism through support for the German resistance. In the postwar period, he actively opposed the spread of communism and clarified Catholic doctrine, including the establishment of the Assumption of Mary as a dogma of the faith and opposition to birth control. After World War II, he actively fought the spread of communism in Europe and Asia, even issuing decrees of excommunication for Catholics who joined communist parties.