Pius XI was born in Italy on May 31,1857, as Achille Ratti, to a working class family in Lombardy, Italy, near Milan. A brilliant student at the Milan Seminary and the Gregorian University in Rome, he taught theology and sacred eloquence. He joined the staff of the famed Ambrosian Library in 1888, where he was chief librarian (1907-1914), then became assistant librarian of the Vatican.
In 1918, at age 60, Pope Benedict XV appointed him as apostolic visitor to the Polish Catholic Church, in the new nation of Poland. In 1920, he was papal nuncio and rallied Catholics by staying in Warsaw when the Soviet Red Army nearly captured that city. In 1921 he was mediator between the German and Polish clergies during the bitter plebiscite over the province of Upper Silesia. After eight months as archbishop of Milan, he was elected pope by the cardinals on Feb. 6, 1922.
He withdrew support from the Catholic Popular Party in order to smooth the way for the Lateran Treaty and the Concordat of 1929 with Benito Mussolini's fascist government of Italy. The Treaty recognized the Vatican as a temporal state of the miniature state of "Vatican City" inside Rome. The Concordat guaranteed the rights of the Church throughout Italy. This brought to an end the bitter animosity between the Italian government and the Papacy, and allowed Catholics to participate in politics.
Pius negotiated a Concordat with Adolf Hitler in 1933, to head off suppression of the Church in Nazi Germany. Pius saw Hitler as an ally against Soviet Communism, which was gaining strength among the dechristianized working classes of Europe's industrial cities.
Shocked by widespread attacks on the clergy and churches and fearful of Communism, Pius gave moral support to Francisco Franco, who upheld the Catholic side in the Spanish civil war against socialists, Communists and anarchists trying to destroy the Church and kill the priests and nuns.
Pius condemned the anti-republican, ultraconservative political movement Action française in 1927, and was outspoken in his criticism of Fascist and Nazi violations of the concordats and their inhumane treatment of the Jews. He issued the encyclical "Mit brennender Sorge" in 1939, in which he condemned Hitler's actions.
Pius was a vigorous leader who encouraged the spiritual activity of the laity in the Catholic Action movement, promoted a reform of the liturgy, and centralized the direction of the missions. A prolific writer, his encyclicals on the family, Christian education, and social justice became well known among Catholics everywhere.
His successor was his secretary of state, Cardinal Eugenio Pacelli, who became Pius XII.