Catholic Encyclopedia (1913)/Guglielmo Sirleto
Cardinal and scholar, born at Guardavalle near Stilo in Calabria, 1514; died at Rome, 6 October, 1585. The son of a physician, he received an excellent education, made the acquaintance of distinguished scholars at Rome, and became an intimate friend of Cardinal Marcello Cervino, later Pope Marcellus II. He prepared for Cervino, who was President of the Council of Trent in its initial period, extensive reports on all the important questions presented for discussion. After his appointment as custodian of the Vatican Library, Sirleto drew up a complete descriptive catalogue of its Greek manuscripts and prepared a new edition of the Vulgate. Paul IV named him prothonotary and tutor to two of his nephews. After this pope's death he taught Greek and Hebrew at Rome, numbering St. Charles Barromeo among his students. During the concluding period of the Council of Trent, he was, although he continued to reside at Rome, the Constant and most heeded adviser of the cardinal-legates. He was himself created cardinal in 1565, became Bishop of San Marco in Calabria in 1566, and a Squillace in 1568. An order of the papal secretary of state, however, enjoined his residence at Rome, where he was named, in 1570, librarian of the Vatican Library. His influence was paramount in the execution of the scientific undertakings decreed by the Council of Trent. He collaborated in the publication of the Roman Catechism, presided over the Commissions for the reform of Roman Breviary and Missal, and directed the work of the new edition of the Roman Martyrology. Highly appreciative of Greek culture, he entertained all friendly relations with the East and encouraged all efforts tending to ecclesiastical reunion. He was attended in his last illness by St. Philip Neri and was buried in the presence of Sixtus V.
HURTER, Nomenclator Lit., I (2nd ed., Innsbruck, 1892), 95-6; BÄUMER-BIRON, Hist. du bréviaire, II (Paris, 1905), 169-71, passim.