large proportion of those in his library were the work of his own hand. At his death in 1437 he bequeathed 800 manuscripts to Cosmo de' Medici and fifteen other trustees, among whom were Ambrogio Traversari and Poggio.
This noble bequest was worthily used by Cosmo de' Medici, who stands out as the first great founder of libraries at the Renaissance. Already, in his exile from Florence, he had founded at Veniqe, in 1433, the Library of San Giorgio Maggiore. In 1441, when the new hall of the Convent of San Marco at Florence was ready to receive books, he placed there 400 of Niccoli's volumes. Of the other 400 the greater part passed into his own large collection, which became the nucleus of the Medicean Library. For the new Abbey which he had built at Fiesole he also provided a library, giving a commission to Vespasiano, who set forty-five copyists to work, and produced 200 manuscripts in twenty-two months. The Medicean collection, joined to those of San Marco and of the Abbey at Fiesole, form the oldest part of the books now in the Biblioteca Mediceo-Laurenziana.
Another great library which first took shape in the fifteenth century is that of the Vatican. A papal library of some sort had existed from very early times, and had received from Pope Zacharias (741-52) a large addition to its stock of Greek manuscripts. This old collection had been deposited in the Lateran. When the papal Court was removed to Avignon in 1309, the books were taken thither. The Great Schism, which began in 1378, was closed by the election of Martin V in 1417. The books were subsequently brought back from Avignon to Rome, and placed in the Vatican. Eugenius IV (1431-47), who came next after Martin V, interested himself in this matter. But his successor, Nicholas V (1447-55), has the best claim to be called the founder of the Vatican Library. As Tommaso Parentucelli, he had catalogued the Library of San Marco at Florence for Cosmo de' Medici. He was thus well qualified to build up a great collection for the Vatican. During the eight years of his pontificate, he enlarged that collection with energy and judgment, adding to it several thousands of manuscripts. The number of Latin manuscripts alone was, at his death, 824, as is shown by a catalogue dated April 16, 1455. He had intended also to erect a spacious library, which should be thrown open to the public; but he did not live to execute that design. His successor, Calixtus III (1455-8), added many volumes brought from Constantinople after its capture by the Turks. Sixtus IV (1471-84),—Francesco della Rovere, a Franciscan monk of learning and eloquence,—became the second founder of the library. In 1475 he appointed as librarian the erudite Bartolommeo Sacchi, known as Platina from the Latinised name of his birthplace Piadena. Under the supervision of Platina, to whom Sixtus IV gave a free hand, the collection was lodged in its present abode, a suite of rooms on the ground-floor of a building in the Vatican which had been