Francesco di Giorgio, in his Treatise on Architecture, mentions Duke Federigo as holding out inducements for the learned men at his court to illustrate the works of classic authors on architecture and sculpture. But no testimony to his literary habits can be more satisfactory than that of his librarian Vespasiano, to the following purpose.[180] The Duke was a ready Latin scholar, and extremely fond of ancient history. As a logician he had attained considerable aptitude, having studied Aristotle's Ethics along with Maestro Lazzaro, a famous theologian, who became Bishop of Urbino, discussing with him the most intricate passages. By the like process he mastered the Stagirite's politics, physics, and other treatises; and having acquired more philosophy than any contemporary prince, his thirst for new sources of knowledge induced him to devote himself to theology with equal zeal. The principal works of St. Thomas Aquinas and Duns Scotus were habitually read to him; he preferred the former as more clear, but admitted that the latter displayed greater subtlety in argument. He was well acquainted with the Bible, as well as the commentaries of Saints Ambrose, Jerome, Augustine, and Gregory; also with the writings of the Greek fathers, such as Saints Basil, Chrysostom, Gregory Naziazen, Nicetas, Athanasius, and Cyril. Among the classic authors whom he was in the habit of reading or listening to were Livy, Sallust, Quintus Curtius, Justin, Cæsar, Plutarch, Ælius Spartianus, Æmylius Protus, Tacitus, Suetonius, Eusebius. All men of letters visiting Urbino were hospitably entertained, and several were always attached to his court. His largesses to such were at all times liberal. He spent above 1500 ducats in this way when at Florence, and remitted similar bounties to Rome and Naples. He gave 1000 ducats to the learned Campano, professor of belles-lettres at Perugia in 1455,[*181] who aided him in collecting ancient MSS., and became Bishop of Teramo. Nor were elegant accomplishments neglected. His acquaintance with the principles and practice of architecture excelled that of most contemporaries in any station, enabling him to superintend personally the plans and execution of his palaces and other buildings. He was equally at home in military engineering, and applied to his numerous fortified places such modifications as the introduction of artillery required, especially in reducing their altitude. The kindred sciences of geometry and arithmetic were his favourite studies, and not long before his death, he had a course of these read to him by Maestro Paolo, a learned German astrologer, retained at his court. In music, his taste and knowledge were excellent; there were in his chapel and palace bands of choristers and skilful performers, the organ being his favourite instrument. He was familiar with sculpture, and adopted it in the ornaments of his palace. He brought from Flanders a celebrated painter in oil, and