Several sections of the exhibit are dedicated to the Vatican’s actions during the war. Pope Pius is described as a “defender of peace” who opened Vatican properties to refugees and created an office to help prisoners of war and their families.

The pope is pictured standing amid the Roman populace after aerial bombardment of the city, visiting the Vatican bakery that furnished free bread to residents, and meeting in 1943 with Jews who escaped deportation to concentration camps.

Press clippings and letters attesting to the pope’s courage in defending the Jews are included, along with transcripts of the pope’s radio broadcasts during the war.

To help demonstrate the pope’s clear anti-Nazi sentiments, one glass case displays pages of a draft version of the 1937 encyclical With Burning Concern which condemned the racism and paganism of the Nazi regime. The text was written by Pope Pius XI, but with assistance from his secretary of state, then-Cardinal Eugenio Pacelli — elected two years later as Pope Pius XII — whose margin notes are clearly visible.

The exhibit opened as an international debate continued over the late pope’s actions during the war. Some Jewish groups have said he did little to mobilize the church in defence of Jews, while other experts have gathered evidence to show that he worked quietly but effectively to save the lives of thousands of Jews and others.

Msgr. Walter Brandmuller, president of the Pontifical Committee for Historical Sciences, told a press conference that the exhibit should help demonstrate that “the accusations against (Pope Pius XII) cannot be based on historical research, which ever more convincingly demonstrates how groundless they are.”

Much of the Vatican exhibit presents a human side of the pope, including his early years as a boy in a neighbourhood not far from the Vatican. It also highlights aspects of his pontificate that are often overlooked: his launching of archeological excavations beneath St. Peter’s Basilica, his interest in contemporary artistic works and his extensive travels.

One of the most unusual items is a handwritten page in which the pope gave an account of witnessing the so-called “miracle of the sun,” seeing the sun rotate and move in the sky. The episode occurred in the Vatican Gardens, the day before the pope proclaimed the dogma of the Assumption of Mary in 1950.

The section titled “The Private Pope Pius” features a photo of him petting two lambs at his Castel Gandolfo country residence.

Another photo shows him with a pet canary perched on his finger; it was one of several pet birds that would fly around his dining-room table as he dined alone.

The exhibit runs to Jan. 6.