After decades of pressure from historians and Jewish groups, the Vatican began allowing scholars access to Word War-2 era Archives of Pope Pius XII, CNN reported.
Scholars and Jewish groups have been asking for decades that the archives, which contains millions of letters, cables and correspondence from Pius XII's 1939-1958 pontificate, be made available for study.
Pope Francis took the decision a year ago to open up the archives.
"The Church is not afraid of history," the Pope told Vatican researchers.
According to media reports, the Vatican's Chief Librarian, Cardinal José Tolentino Calaça de Mendonça, said all researchers, regardless of nationality, faith and ideology, are welcome.
In the years immediately following the war, Pius XII was praised by world leaders, including Israel's then-Prime Minister Golda Meir. However, his reputation began to deteriorate in the 1960s when Rolf Hochhuth's play "The Deputy" accused the Pope of being silent in the face of the Nazi extermination of Jews. Other books critical of Pius XII followed, such as "Hitler's Pope," by John Cornwell in 1999, and "Under His Very Windows" by Susan Zuccotti in 2000.