Pope Francis has announced that he will open up the Vatican’s secret archives on the papacy of Pope Pius XII, who has been accused of failing to speak up about the Nazis’ persecution of the Jews.

Historians have for decades been calling on the Holy See to let scholars study the archives, in order to determine whether Pius XII failed to use his moral authority to oppose the Holocaust.

The argument that Pius should have been far more vocal in condemning the Nazis’ annihilation of six million Jews was put forward most forcefully in the 1999 book Hitler’s Pope, by John Cornwell, a British writer and academic.

Pope Francis announced his decision during a meeting with staff from the Secret Archives, part of the Vatican’s vast repository of documents and records, declaring that “the Church is not afraid of history”.

He said the archive would be opened on March 2 next year to mark the 81st anniversary of the election of Pius XII in 1939.

Francis acknowledged that there had been “moments of grave difficulty and tormented decisions” for the wartime pontiff, saying he had been treated by posterity with “some prejudice and exaggeration”.

Without referring directly to Pius’s actions towards the Jews of Europe, Francis said his predecessor had engaged in “hidden but active diplomacy” in order to pursue “humanitarian initiatives”.