Pope Pius XII was elected pope in March 1939 when Europe was gripped by fear of war. Although he appealed for peace and tried to play a diplomatic role, he is criticized for not standing up to Nazi aggression. When Hitler occupied Rome in 1943, Pius XII turned the Vatican into a safe asylum for refugees, including Jews, but he failed to condemn the Nazis for their brutalities. He is rumored to have known about the Holocaust and remained silent out of fear of Nazi retaliation.