during the Middle Ages. Of the Church Fathers, St. Augustine, St. Jerome and even more so St. Thomas Aquinas, are known to have been familiar with it. Illustrating its importance, some 700 handwritten copies remain extant in libraries around the world dating back to before the invention of the printing press. Though this does not surpass the Latin grammarian Priscian's 900 extant handwritten copies, it places De Officiis far above many classical works. Following the invention of the printing press, De Officiis was the third book to be printed—third only to the Gutenberg Bible and Donatus's "Ars Minor", which was the first printed book. Petrarch, the father of humanism and a leader in the revival of Classical learning, championed Cicero. It is suspected that Machiavelli's The Prince is at least in part meant to be a direct refutation of Cicero's De Officiis. is Several of his works build upon the precepts of De Officiis. Prince Peter, Duke of Coimbra, member of the Order of the Garter, translated the treatise to portuguese in 1437, signal of the wide spread of the work in medieval courts. The Catholic humanist Erasmus published his own edition in Paris in 1501. His enthusiasm for this moral treatise is expressed in many works. The German humanist Philip Melanchthon established De Officiis in Lutheran humanist schools. T. W. Baldwin said that "in Shakespeare's day De Officiis was the pinnacle of moral philosophy". Sir Thomas Elyot, in his popular Governour (1531), lists three essential texts for bringing up young gentlemen: Plato's works, Aristotle's Ethics, and De Officiis. In the 17th century it was a standard text at English schools (Westminster and Eton) and universities (Cambridge and Oxford). It was extensively discussed by Hugo Grotius and Samuel von Pufendorf. Grotius drew heavily on De officiis in his major work, On the Law of War and Peace. It influenced Robert Sanderson and John Locke. In the 18th century, Voltaire said of De Officiis "No one will ever write anything more wise". Frederick the Great thought so highly of the book that he asked the scholar Christian Garve to do a new translation of it, even though there had been already two German translations since 1756. Garve's project resulted in 880 additional pages of commentary. In 1885, the city of Perugia was shaken by the theft of an illuminated manuscript of De Officiis from the city's Library Augusta. The chief librarian