Pope Francis
Pope FrancisUri Lenz/POOL/Flash 90

Jewish groups on Monday praised the Vatican's decision to open the archives of Pius XII, who was pope during the World War II period.

The American Jewish Committee said in a statement that, for more than 30 years, it "has called for the full opening" of the archives "to shed light on his activities as pontiff during World War II.”

Pope Francis announced Monday that the Vatican will open the secret archives in March 2020.

The announcement comes just ahead of an AJC delegation visit to the Vatican and audience with the Pope this week.

Pope Francis's decision to open the archives "is enormously important to Catholic-Jewish relations," said AJC International Director of Interreligious Affairs David Rosen.

It is important for experts to "objectively evaluate as best as possible the historical record of that most terrible of times - to acknowledge both the failures as well as the valiant efforts made during the period of the systematic murder of six million Jews," Rosen said.

Researchers have long sought to examine the archives to understand why Pius XII (1939-1958) did not intervene more against the Holocaust perpetrated by the German Nazis, an attitude denounced by critics including Jewish groups as a form of passive complicity.

The Anti-Defamation League (ADL) also welcomed the announcement by Pope Francis.

“The opening of the Vatican’s archives is an extraordinarily important announcement and a welcome moment in the history of Catholic-Jewish relations,” said Rabbi David Fox Sandmel, ADL Director of Interreligious Dialogue. “The inaccessibility of the archives has been a continued source of tension in Jewish-Catholic relations and a frustration for historians. Assuming all of the documents will be made available to researchers, then this is precisely what historians and those of us concerned about an accurate account of the actions of the pope and the Vatican during the war have been asking for. What transpired during those years cannot be known and assessed until researchers have complete access to the archives.”

ADL has been calling for the archives to be fully opened to scholars and historians for decades, as the Vatican usually waits 70 years after the end of a pontificate to open up relevant archives. At an international conference of Vatican and Jewish interfaith leaders in Paris in 2011, ADL requested a special conference to discuss opening the Vatican's secret World War II archives for humanitarian purposes: for the sake of aging Holocaust survivors and their families. The issue was raised again during the first official meeting between Pope Francis and Jewish leaders on June 24, 2013 in Rome.

“The issue of what Pius XII did or did not do to help save Jews during the Holocaust is a profound question that must be resolved, especially as efforts are underway to declare him a saint,” said Rabbi Sandmel. “To proceed on the process toward sainthood without having all of the facts would be premature when so much is not known about the historical truth.”

AFP contributed to this report.