The Pope and Mussolini: The Secret History of Pius XI and the Rise of Fascism in Europe

David Kertzer builds his account of Pope Pius XI, a former Vatican librarian and expert mountaineer elected pope in 1922, around one of the most consequential and compromised relationships between the Catholic Church and a fascist government in modern history. The book follows Pius XI from his election through the 1929 Lateran Treaty, the settlement that finally ended decades of hostility between the papacy and the Italian state, gave Vatican City its own sovereignty, and paid the Church 1.75 billion lira in compensation for property Italy had seized generations earlier.

Kertzer traces how that early cooperation curdled once Mussolini's fascist state began reaching directly into Catholic youth organizations, prompting Pius XI's own 1931 encyclical Non Abbiamo Bisogno condemning what he called the pagan worship of the state, and follows the pope toward his sharper 1937 encyclical against Nazism, Mit Brennender Sorge, written in German and smuggled into churches for reading from the pulpit. The book draws on Vatican Secret Archive material opened only in the years before Kertzer wrote, using internal Church correspondence to show how far the Vatican's private accommodations with Mussolini's government went even as Pius XI's public statements grew more critical, right up to his death in February 1939 at eighty one.

Kertzer writes as a historian working from documents the Church itself had kept closed for decades, and reading the book means following how a supposedly neutral institution actually negotiated, compromised and occasionally resisted a fascist state from the inside. It suits a reader who wants the moral complexity of that relationship, not a simple story of either collaboration or resistance, laid out from the paper trail itself.