Scholars have traditionally divided the history of the library into five periods, Pre-Lateran, Lateran, Avignon, Pre-Vatican and Vatican.
The Pre-Lateran period, comprising the initial days of the library, dated from the earliest days of the Church. Only a handful of volumes survive from this period, though some are very significant.
The Lateran era began when the library moved to the Lateran Palace and lasted until the end of the 13th century and the reign of Pope Boniface VIII, who died in 1303, by which time he possessed one of the most notable collections of illuminated manuscripts in Europe. However, in that year, the Lateran Palace was burnt and the collection plundered by Philip IV of France.
The Avignon period was during the Avignon Papacy, when seven successive popes resided in Avignon, France. This period saw a great growth in book collection and record keeping by the popes in Avignon, between the death of Boniface and the 1370s when the Papacy returned to Rome.
The Pre-Vatican period ranged from about 1370 to 1446. The library was scattered during this time, with parts in Rome, Avignon and elsewhere.
In 1451, bibliophile Pope Nicholas V sought to establish a public library at the Vatican, in part to re-establish Rome as a destination for scholarship. Nicholas combined some 350 Greek, Latin and Hebrew codices inherited from his predecessors with his own collection and extensive acquisitions, among them manuscripts from the imperial Library of Constantinople. Pope Nicholas also expanded his collection by employing Italian and Byzantine scholars to translate the Greek classics into Latin for his library. The knowledgeable Pope already encouraged the inclusion of pagan classics. Nicolas was important in saving many of the Greek works and writings during this time period that he had collected while traveling and acquired from others.
In 1455, the collection had grown to 1200 books, of which 400 were in Greek language.
Nicholas' death in 1455 prevented the completion of his vision of a public library, but it was finished in 1475 by his successor Pope Sixtus IV, and named the Palatine Library. During the papacy of Sixtus IV, acquisitions were made in "theology, philosophy and atristic literature". The number of manuscripts is variously counted as 3,500 in 1475 or 2,527 in 1481, when librarian Bartolomeo Platina produced a signed listing. At the time it was the largest collection of books in the Western world.
During his reign, Pope Julius II commissioned the expansion of the building. Around 1587, Pope Sixtus V commissioned the architect Domenico Fontana to construct a new building for the library, which is still used today. It was after this the library became known as the Vatican Library.
During the Counter-Reformation, access to the library's collections was limited following the introduction of the Index of banned books. Scholars' access to the library was restricted, particularly Protestant scholars. Restrictions were lifted during the course of the 17th century, and Pope Leo XIII formally reopened the library to scholars in 1883.
In 1756, Abbot Piaggio conserver of ancient manuscripts in the Vatican Library used a machine he also invented, to unroll the first Herculaneum papyri, which took him months.
In 1809, Napoleon Bonaparte arrested Pope Pius VII, and removed the contents of the library to Paris. The contents were returned in 1817, three years after the defeat of Napoleon.
In 1992 the library had almost 2 million catalogued items.
In 1995 art history teacher Anthony Melnikas from Ohio State University stole three leaves from a medieval manuscript once owned by Francesco Petrarch. One of the stolen leaves contains an exquisite miniature of a farmer threshing grain. A fourth leaf from an unknown source was also discovered in his possession by the U.S. Customs agents. Melnikas was trying to sell the pages to an art dealer, who then alerted Father Leonard E. Boyle, the librarian director.