THINGS are different when you are the Pope, a friend of Jorge Mario Bergoglio warned me just a few weeks after the Cardinal Archbishop of Buenos Aires became the first Pope Francis.

We were chatting in a bar in central Buenos Aires. I had just come back from interviewing Rabbi Abraham Skorka, a leading figure in the Jewish community in Argentina, to whom the future Pope had become close over the years - so much so that the two had together written a book called On Heaven and Earth.

Among the subjects on which it touched was the controversy over the wartime Pope, Pius XII. "There are two views," Rabbi Skorka had told me. "One is that he did all he could to save Jews without confronting the Nazis, which mighthave accelerated the killing of Jews. The other asks how Pius XII could have stayed silent and not shouted to all the winds: 'Stop killing innocent people.' Bergoglio said: 'We must open the Vatican archives, and find out the truth.' Now he has the chance to do that. I'm confident he will."

Not everyone was so sure. That other friend of Bergoglio told me that what a man said as a cardinal could not always be acted upon once he became Pope - and Pius XII was a tricky subject. As Archbishop Eugenio Pacelli, he had been Papal Nuncio to Bavaria. In the early years he ridiculed the Nazis as "miserable plagiarists who dress up old errors with new tinsel", declaring them to be "profoundly anti-Christian and a danger to Catholicism".

But later he signed a concordat with Hitler that granted freedom of practice to Roman Catholics in return for the Church's keeping out of politics. During the Second World War, Pius XII kept the Vatican, which was surrounded by fascist Italy, strictly neutral.

Throughout the Holocaust, the Pope was besieged with pleas - from the Chief Rabbi of Palestine, the Ukrainian Metropolitan, the US representative to the Vatican, a Polish diplomat, a German bishop, and the future Pope Paul VI - to aid the persecuted Jews. Privately, Pius XII instructed monasteries and convents to take in Jews. But he did not speak out; nor did he warn Jews in Rome before they were rounded up.

Historians offer a variety of criticisms and defences. Critics say that he was anti-Semitic, and sought to save only Jews who were baptised Christians. Defenders say that he feared Nazi reprisals if he spoke out, insisting that private intervention could accomplish more. Others believe that he saw Russia's atheistic Communism as a greater threat to the Church than Fascism. But historians lack the insights that Vatican documents would reveal.

Last week, Rabbi Skorka visited Pope Francis in Rome, and announced that his old friend was still determined that the 1940s documents should be made public. The Pope is said to be about to act on what he said in On Heaven and Earth, where he wrote of the archives: "Let them be opened up and let everything be cleared up. Let it be seen if they could have done something [to help] . . . the truth has to be the goal."

Pius XII had previously entered the second of the four stages that would lead to his being declared a saint. It may now be that he will proceed no further.
 

Pope Francis: Untying the Knots by Paul Vallely is published by Bloomsbury.