The Compleat Gentleman by Brad Miner (Spence Publishing, 2004), however, goes much deeper into the subject, beyond manners and manly fashion. From a book review by Fr. John McCloskey:
Miner goes about his examination of the gentleman by considering various aspects of this term and its history. He sees its origin in early feudal medieval times, in the knight who wages war on horseback in heavy armor, in service to his feudal lord, when not competing in tournaments. Very early, the institution of knighthood became allied with Catholicism and with the idealization of women called "courtly love." The knight, though brutal in warfare, must be virtuous in his personal behavior, particularly to women, children and the poor.
In the Renaissance, the idea of the gentleman developed in the courts of kings and noblemen. There have always been two senses of the word: the fine man of high birth and the fine man of high character. The latter sense has always been the most important. To nearly everyone, it also meant a standard of conduct, "a standard, to which the best born did not always rise and which even the humblest might sometimes display." Castiglione's Courtier, written in the early 1500s, became the textbook for this new approach. The gentleman became more intellectually serious. He is "urbane" and elaborately civil. He will not only have knowledge, but "knowledge integrated: of refinement, sophistication, elegance, courtesy… plus suavity."
Miner tells us his book is "about an ideal. No man behaves as a compleat gentleman all the time, but the best men never cease yearning to." He says the aristocracy of gentlemen "is, in fact, a brotherhood of virtue." Miner makes clear that the virtue he prizes above all is courage.
Read the whole thing at McCloskey's Perspectives