The Vatican Secret Archives, containing millions of documents spanning 12 centuries, are no longer officially “secret”.

Pope Francis has renamed the priceless archives, which include letters concerning King Henry VIII’s request to divorce Catherine of Aragon and marry Anne Boleyn, which led to the English church breaking away from Rome in 1534.

They also hold the original acts of the 1633 trial of the astronomer Galileo by the Roman Inquisition, which condemned him as a heretic for teaching that the Earth revolves around the sun.

The Vatican said on Monday the new name would be the Vatican Apostolic Archives. This removes any potentially “negative nuances” from the Latin word “secretum”, which the pope said in a decree was closer to “private” or “reserved” than “secret” when the archives were first named in about 1610.

They have not been secret in practice for a long time anyway: like most state archives, they are open to qualified researchers after a period of time. The collection of papers, documents and parchments dates as far back as the eighth century, making the archives one of the world’s most important research centres.

They contain 53 miles (85km) of shelving and an underground vault known as “the Bunker”, a version of which was recreated in the film version of the Dan Brown novel Angels and Demons.

The archives are open for the period of the pontificate of Pope Pius XI, ending in 1939. Those from the pontificate of Pius XII (1939-58) are due to be opened to scholars next March, an event which has been keenly awaited by the Jewish community; many Jews and historians say Pius did not do enough to help those facing persecution by Nazi Germany.

The Vatican maintains that Pius chose to work behind the scenes, concerned that public intervention would have worsened the situation for both Jews and Catholics in a wartime Europe dominated by Hitler.

When Francis announced the date of the opening last March, he said Pius’s legacy had been treated with “some prejudice and exaggeration”.