The student also said Tardini is an important figure for him and his research "because he wrote a lot" -- and not just official documents.
He said that he found many helpful notes written by Tardini especially in documents from during the pontificate of Pius XI.
"I found really great notes, not because they show who knew [something], or some great scoop or some big discovery relative to the official history, but because they let you see how Tardini entered into problems," he observed.
The notes "let you see also how so many questions of the official history must be read inside the folds of history. It is going into depth. You see how complex many problems were. And Tardini's notes help us to understand this."
Before his election as pope, Pius XII was secretary of state. After his election he nominated Cardinal Luigi Maglione to take over the role, but Maglione died suddenly in 1944 from heart problems, leaving the seat vacant again.
Pius XII did not name a new secretary of state, preferring to take over the responsibilities of the position himself, with the help of the heads of the two sections, Msgr. Tardini and the sostituto Msgr. Giovanni Battista Montini, the future Pope Paul VI.
The two "worked directly with Pius XII in the carrying out of the diplomatic affairs," Aira explained.
In his position, Tardini had his own meetings with ambassadors and diplomats; he was also present and took notes at many of Venerable Pius XII's audiences.
Aira said that Tardini's notes gave detailed descriptions of what happened and what was said. In the notes verbale -- a specific type of diplomatic note -- the monsignor would write in the margins his recommendations for what the pope should say or do.
"I think he's a key character," Aira said. "Even because, as I was saying, not only did he have historic roles, key roles for so many years, roles that put him near three popes, Pius XI, Pius XII, and John XXIII … but also because he was a person considered by collaborators, by witnesses, to have a very lively, profound, intuitive intelligence, with the ability to enter into situations."
Tardini, he continued, was a "Roman of Rome," and brought "the sense of his priesthood" into his work. The priest wanted to "really live pontifical diplomacy, and service to the pope, not like maybe a company with account balances, but really with a priestly spirit, with a very important ecclesial mission."
(Story continues below)
Subscribe to our daily newsletter
"Service to the pope was an extraordinary thing to him, however, he did things in a blunt way," the researcher noted, adding that no one described Tardini as "sentimental."
"He was a concrete, courageous person. He said what he was thinking. But he was also prudent. Because that which he said, which he wrote, he did because he believed in the service to the pope and to the Holy See, without ever wanting to put himself forward."
Tardini also wrote down many personal recollections.
Bishop Sergio Pagano, prefect of the Vatican Apostolic Archive, published a book of the private papers of Tardini in March, after the opening of the Pius XII archives.
Aira said Pagano notes in his book that after Pius XII's death and the election of Pope John XXIII, the cardinal "was already thinking to use these notes to write a real history of the papacy to bring to light the importance and the service the pope rendered toward humanity in the critical years of the war."
"Then death came."