In addition to these increased opportunities of exercise, he also derived much assistance, in the more obscure and uncommon department of his peculiar studies, from the libraries of Rome, and especially from that of the Propaganda. The early elementary books, grammars, vocabularies, catechisms, &c., prepared for the use of missionaries in the remote missions, have for the most part been printed at the Propaganda press: and the library of that institution contains in manuscript similar elementary treatises in languages for the study of which no printed materials existed at that time. To all these, of course, the great linguist enjoyed the freest access; and it can hardly be doubted that, during the first year of his residence in Rome, he did more to enlarge his stock of words, and to perfect his facility and fluency in conversation, than perhaps in any previous year of his life. Immediately upon Mgr. Mai’s appointment to the Secretaryship of the Propaganda, May 15th, 1833, Mezzofanti was installed as _Primo Custode_, First Keeper of the Vatican Library; and about the same time he was appointed to a Canonry in St. Peter’s. In the midst of the warm congratulations which he received from all sides, it was not without considerable distrust of his own powers, that he entered upon the office of Librarian, as the successor of a scholar so eminent as Angelo Mai. “It is no ordinary distinction,” he wrote to his friend Cav. Pezzana, “to be called to succeed Mgr. Mai in the care of the Vatican Library,—a post which has derived new brilliancy from the brilliant qualities of its latest occupant: nor can I overcome my apprehension lest the honour which I may gain by my first few hours of office may decline, when it comes to be seen how great is the difference between this distinguished man and his successor. This fear, I confess, is a drawback upon my joy at this happy event; but at the same time, I trust it will also stimulate me to make every effort that the lustre of a position in itself so honourable, may not be tarnished in my person. I have only to wish that your congratulation, coming as it does from a kindly feeling, may be an earnest of the successful exercise of the diligence I am determined to use in my new career, which is all the more grateful and honourable to me, as it furnishes more frequent occasions of corresponding with you.”