Pius XII (1876-1958), pope from 1939 to 1958, guided the Roman Catholic Church through the difficult years of World War II and the postwar period, when much of the eastern Catholic Church was heavily persecuted by Soviet communism.

Pius XII was born Eugenio Maria Giuseppe Pacelli in Rome on March 2, 1876. Because of poor health he was allowed to study for the priesthood at his home. Ordained a priest in 1899, he took up work in the Vatican Secretariat of State in 1901, working there until 1917. In that year he became archbishop of Sardis and was sent to Munich as apostolic nuncio to Bavaria. In 1918 he became nuncio in Berlin to the new Weimar Republic. During his German years Pacelli acquired a love of the German people and a knowledge of German affairs. He was a close observer and on a few occasions an eyewitness of Bolshevik riots in Germany, which developed a...