Pius XI

According to the telegrams, the Vatican embassy sent what U.S. churches had collected from the American faithful, down to the cents: $210,400.09, allowing the vote that eventually elected Pope Pius XI.

In 1930, his successor Pope Pius XI issued 12 rules designed to assure that "feminine garb be based on modesty and their ornament be a defense of virtue."

In 2014, he published “The Pope and Mussolini,” examining Pius XI’s role in the rise of fascism and the antisemitic Racial Laws of 1938.

Four decades later, Pope Pius XI’s encyclical of 1931 was cited by Franklin Roosevelt on the campaign trail as “one of the greatest documents of modern times.”

“Among historians, my piece I think will be fairly explosive,” said Dr. Kertzer, whose book “The Pope and Mussolini,” about Pius’s predecessor, Pius XI, won the Pulitzer Prize for biography in 2015.