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.

[7] In later centuries, as the Church amassed power, popes would visit heads of state to negotiate treaties or make political appearances around Europe.

The Western Schism resulted in two sets of papal archives being developed at once; this rose to three during the era of Pisan antipope John XXIII.

[7] During the 1404 sack of the Vatican, papal registers and historical documents were thrown into the streets, and Pope Innocent VII fled the city.

His successor, Pope Gregory XII, supposedly sold off a large number of archival materials in 1406, including some of the papal registers.

The 1798 Treaty of Tolentino made even greater demands, and the works sent to Paris included the Codex Vaticanus, the oldest extant manuscript of the Bible in Greek.

In April 1814, after Coalition troops entered Paris, the new French government ordered the archive returned, but provided inadequate financing.

[a] Inadequate funding led to losses en route, with one scholar of the period estimating that "about one-fourth to one-third of the archival materials that went to Paris never returned to the Vatican.

Beginning in 1867, Theiner and his successor granted individual scholars access to the manuscripts relating to the trial of Galileo, leading to a protracted dispute about their authenticity.

[14] In 1879, Pope Leo XIII appointed as archivist Cardinal Josef Hergenröther, who immediately wrote a memo recommending that historians be allowed access to the archive.

[15] When the German Protestant historian Theodor von Sickel, in April 1883, published the results of his research in the archive, which defended the Church against charges of forgery,[c] Pope Leo was further persuaded.

In August 1883 he wrote to the three cardinals who shared responsibility for the archives and praised the potential of historical research to clarify the role of the papacy in European culture and Italian politics.

"[16][17] In 1979, historian Carlo Ginzburg sent a letter to the newly elected Pope John Paul II, asking that the archives of the Holy Office (the Roman Inquisition) be opened.

[20] In 2018, Pope Francis ordered the Vatican Archive to open documents which would assist in a "thorough study" concerning former Cardinal Theodore McCarrick, who was accused of sexually molesting seminarians and having affairs with young priests.

[28] Notable documents include Henry VIII of England's request for a marriage annulment, a handwritten transcript of the trial of Galileo for heresy, and letters from Michelangelo complaining he had not been paid for work on the Sistine Chapel.

[35] In 2017, a project based in Roma Tre University called In Codice Ratio began using artificial intelligence and optical character recognition to attempt to transcribe more documents from the archives.