original name Achille Ratti. 1857–1939, Italian ecclesiastic; pope (1922–39). He signed the Lateran Treaty (1929), by which the Vatican City was recognized as an independent state. His encyclicals condemned Nazism and Communism
Italian pope from 1922 to 1939, one of the most important modern pontiffs whose motto "the peace of Christ in the Kingdom of Christ" illustrated his work to construct a new Christendom based on world peace.
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