When disabled from the profession of arms, he fell back with fresh zest upon his youthful studies, and drew around him men whose converse harmonised with these tastes. To say that his learning was unequalled among the princes of his day is no mean compliment. His palace became the asylum of letters and arts, over which he gracefully presided. Aldus Manutius, in dedicating to him editions of Thucydides and Xenophon, addressed him in Greek, of which he was so perfect a master as to converse in it with ease. To the latter of these historians the Duke was very partial, calling him the siren of Attica. Among his other favourite classics, Castiglione names Lucian, Demosthenes, and Plutarch; Livy, Tacitus, Quintus Curtius, Pliny, and the Orations of Cicero. Most of these he knew intimately, and recited entire passages without reference to the book. But besides these selected authors, he is said to have made himself acquainted with almost every branch of human knowledge then explored. Nor were religious studies omitted. The history, rites, and dogmas of the Church are mentioned among the topics familiar to his versatile genius; St. Chrysostom and St. Basil were among his chosen books. To enumerate all the contemporary authors who shared his patronage might be irksome, but we shall introduce one letter addressed by him to Paolo Cortesio. "Most reverend and well-beloved Father in Christ: "I have received your letter, with your Treatise on the dignity of Cardinal, which, being full of noble matter gracefully and eloquently handled, has been most acceptable, and I have looked over it with much pleasure. I therefore offer you my best thanks for it, and for having mentioned me in that work; and if I can do anything for you, let me know it, that I may have an opportunity of showing my gratitude for your merits and your services in my behalf. In October next I mean, God willing, to return to Rome, and I shall hold myself prompt to forward your interests there, or wherever else I may chance to be. Urbino, 18th of June, 1506. "GUIDO UBALDO, DUKE OF URBINO, and Captain-General of the Holy Roman Church."[61] [Footnote 61: Bibl. Magliab. Class. viii., No. 68, p. 132.]