Vatican opens archives on history's most controversial pope

The Vatican unseals the archives of history's most contentious popes on Monday, potentially shedding light on why Pius XII stayed silent during the extermination of six million Jews in the Holocaust.

Two hundred researchers have already requested access to the mountain of documents, made available after an inventory that took more than 14 years for Holy See archivists to complete.

Award-winning German religious historian Hubert Wolf will be in Rome on Monday, armed with six assistants and two years of funding to start exploring documents from the "private secretariat" of the late pope.

Wolf, a specialist on the relationship of Pius XII with the Nazis, is anxious to discover the notes of the his 70 ambassadors -- the pontiff's eyes and ears during his time as head of the Catholic Church between 1939 and his death in 1958.

There should also be records of urgent appeals for help from Jewish organisations, as well as his communications with the late US President Franklin D. Roosevelt.

The unsealed archives additionally cover a post-World War II era in which writers were censored and some priests hounded for suspected communist sympathies.

The Vatican first published the essentials covering the Holocaust four decades ago, an 11 volume work compiled by Jesuits.

But some crucial pieces are still missing, including the pope's replies to notes and letters -- for example, those about Nazi horrors.

The Jesuits already published "documents the pope received about the concentration camps, but we never got to see his replies," Wolf said in an interview.

"Either they do not exist, or they are in the Vatican," he told AFP.

Historians have already examined the 12 German years of Eugenio Pacelli, the future pope's real name which he used while posted there as the Holy See ambassador in 1917-1929 There, he witnessed the rise of Nazism, then returned to
"What really interests us is when he learned about it for the first time, and when he believed that information."