The nucleus of the present magnificent collection of books and manuscripts was formed in the Lateran Palace in the year 465 by Bishop Hilary; and, augmented by succeeding pontiffs, the accumulated stores were transferred in 1450 by Pope Nicholas V., the founder of Glasgow University, to the Vatican.  What Nicholas began was completed by Sixtus IV.  The library was classified according to subjects and writers, and Demetrius Lucensis, under the direction of Platina, made a catalogue of it which is still in existence.  During this period Vatican MSS. were lent out to students, as attested by authentic registers containing the autographs of those who enjoyed the privilege.  A little later the celebrated Vatican printing press was annexed to the library; and the office of correctors or readers for the accurate printing of ancient books which were wanting in the library was instituted.  Pope Sixtus V. erected the present splendid edifice, and used every effort to increase the great collection.  Several valuable accessions were made to it after this date, including the library of the Elector Palatine of Germany, the library of the Dukes of Urbino, the libraries of Christina, Queen of Sweden, of the Ottoboni, commenced by Pope Alexander VIII., and of the Marquis Capponi, and the MSS. taken from the convent of S. Basilio at Grotta Ferrata.  Under Innocent XIII. in 1721 an attempt was made to prepare for the press a full catalogue of all the MSS. in every language.  It was edited by Joseph Simon Assemani and Stephen Evodius, and three volumes were published.  But the task was found too great for any one’s strength, and was given up finally on account of the political disturbances of the time.

The library is a vast unexplored mine of wealth.  Unknown literary treasures are contained in the closed cabinets.  Among the thirty thousand manuscripts may be hid some of the ancient classical and early Christian treatises, which have been lost for ages, and whose recovery would excite the profoundest interest throughout the civilised world.  A large number of these manuscripts had once belonged to the library of the famous Monastery of Bobbio, in the north of Italy, founded in the year 614 by the Irish St. Columbanus.  The Irish and Scotch monks who inhabited this monastery were in the dark ages the most zealous collectors of manuscripts in Europe.  At the close of the fifteenth century the convent was impoverished and deserted by its lawful occupants; and the Benedictine monks who succeeded them gave away their literary treasures partly to the Ambrosian Library at Milan and partly to the Vatican Library.  Cardinal Angelo Mai, who discovered more lost works and transcribed more ancient manuscripts than any one else, found among these treasures in Milan and Rome several most interesting treatises that had long passed into utter oblivion.