Historians can now pore over secret files from the papacy of Pius XII, who has long faced accusations of being a Nazi sympathiser

New light will be shed on one of the most controversial periods of Vatican history on Monday when the archives on Pope Pius XII – accused by critics of being a Nazi sympathiser – are unsealed.

A year after Pope Francis announced the move, saying “the church isn’t afraid of history”, the documents from Pius XII’s papacy, which began in 1939 on the brink of the second world war and ended in 1958, will be opened, initially to a small number of scholars.