Starting Feb. 15, the Vatican will give scholars access to key pre-World War II archives, which may help to clarify the attitude of Pope Pius XII toward the Nazi persecution of Jews.
The documents will be open for examination in the reading rooms of the Secret Vatican Archives and the Congregation for the Doctrine of the Faith, Vatican spokesman Joaquin Navarro-Valls said in a statement.
The documents deal with relations between the Vatican and Germany during the prewar years of 1922 to 1939.
Pius XI was pope during those years and Archbishop Eugenio Pacelli, the future Pope Pius XII, served first as ambassador to Germany and then as secretary of state. As Pius XII, he was pope from 1939 to 1958.
The files are expected to have a direct bearing on accusations by English writer John Cornwell in his 1999 book "Hitler's Pope" that Pius XII was anti-Semitic and sympathetic to Adolf Hitler, hoping that the Nazi leader would provide a buffer against communism.
The issue has soured Catholic-Jewish relations and blocked Pius XII's beatification, at least for the present.
Three Catholic and three Jewish historians were named by the Vatican and Jewish agencies in November 1999 to end the controversy over Pius XII's wartime role.
They suspended work in July 2001 because they had been allowed to examine archives only to 1922, plus 11 volumes of already published World War II documents.