Heresies: Triumph of Modernism

In the early 20th century, the Roman Catholic Church had its own secret police. A zealous Vatican functionary, Monsignor Umberto Benigni, set up a group of trusted clerical informers, called the Sodalitium Pianum, to spy on priests and even bishops suspected of heresy. Benigni's ecclesiastical

SMERSH even had its secret code and pseudonyms: then-reigning Pope Pius X was "Lady Micheline," and the Vatican Secretary of State, Cardinal Merry del Val, was "Miss Romey."

The target of Benigni's agents was the heresy of modernism—a broad term encompassing the efforts of certain scholarly priests and...