The Vatican Secret Archives (Archivio Segreto Vaticano) contain the central repository of all the acts that have been promulgated by the Roman Catholic Church's Papal See, as well as diplomatic materials and correspondence of the Papal See and other documents that have accumulated over the centuries. They include some of the seminal historical documents for understanding the real history of the Western world. The Secret Archives were removed from the Vatican Library in the 17th century under the orders of Pope Paul V and remained absolutely closed to Vatican outsiders until the late 19th century, fuelling rumors of what might be secreted away there. The Secret Archives are still separately housed. The first papal historian to make fundamental use of the Secret Archives was the sympathetic historian of the Papacy, Ludwig von Pastor. Documents in the Secret Vatican Archives are open to accredited scholars up to those produced at the end of Pope Benedict XV's pontificate, in 1922.

There are other secret archives at the Vatican. An even more secret archive is kept by the Apostolic Penitentiary and contains papal documents and other material that is hard to assess, because no one is allowed access due to the privacy of the confessor-penitent disputes the Penitentiary is responsible for. Nevertheless the Secret Archives are the main collection. The Vatican Secret Archives have been estimated to contain

The entire contents of the pre-8th century archives, with undoubtedly the world's best collection of heretical texts, have disappeared, according to the Vatican's official account of the library's history, "for reasons not entirely known." The documentation is a little scanty before the 13th century, but there are documents like Henry VIII of England's request for a marriage annulment, and a letter or two from Michelangelo.

Behind its entrance through the Porta S. Anna in via di Porta Angelica, this is the nearest thing the real world offers to the library in Umberto Eco's The Name of the Rose. There is no browsing, selected scholars must ask in advance for the precise document they wish to see, thus they must know in advance that such a document exists. The catalogue is not complete.

On February 20, 2002, Pope John Paul II took the extraordinary step of opening, from 2003, documents concerning Germany and relative to the period 1922–1939 contained in the archives of the Section for Relations with States of the Secretariat of State, in order "to put an end to unjust and thoughtless speculation."

Further reading

Tajne Archiwa Watykanu