Vatican Apostolic Archive
en.wikipedia.org

... The Vatican Apostolic Archive (Latin: Archivum Apostolicum Vaticanum; Italian: Archivio Apostolico Vaticano), formerly known as the Vatican Secret Archive (Latin: Archivum Secretum Vaticanum; Italian: Archivio Segreto Vaticano),[2][3] is the central repository in the Vatican City of all acts promulgated by the Holy See.

The Pope, as the sovereign of Vatican City, owns the material held in the archive until his death or resignation, with ownership passing to his successor. The archive also contains state papers, correspondence, account books,[4] and many other documents that the church has accumulated over the centuries.

Pope Paul V separated the Secret Archive from the Vatican Library, where scholars had some very limited access, and the archive remained closed altogether to outsiders until the late 19th century, when Pope Leo XIII opened the archive to researchers, more than a thousand of whom now examine some of its documents each year.[5]

"Secret" name

The use of the word secret in the former title, "Vatican Secret Archive", does not denote the modern meaning of confidentiality. A fuller and perhaps better translation of the archive's former Latin name may be the "private Vatican Apostolic archive", indicating that its holdings are the pope's personal property, not those of any particular department of the Roman Curia or the Holy See. ...