Knights were expected, above all, to fight bravely and to display military professionalism and courtesy. When knights were taken as prisoners of war, they were customarily held for ransom in somewhat comfortable surroundings. This same standard of conduct did not apply to non-knights (archers, peasants, foot-soldiers, etc.) who were often slaughtered after capture, and who were viewed during battle as mere impediments to knights' getting to other knights to fight them.
Chivalry developed as an early standard of professional ethics for knights, who were relatively affluent horse owners and were expected to provide military services in exchange for landed property. Early notions of chivalry entailed loyalty to one's liege lord and bravery in battle, similar to the values of the Heroic Age. During the Middle Ages, this grew from simple military professionalism into a social code including the values of gentility, nobility and treating others reasonably. In The Song of Roland (c. 1100), Roland is portrayed as the ideal knight, demonstrating unwavering loyalty, military prowess and social fellowship. In Wolfram von Eschenbach's Parzival (c. 1205), chivalry had become a blend of religious duties, love and military service. Ramon Llull's Book of the Order of Chivalry (1275) demonstrates that by the end of the 13th century, chivalry entailed a litany of very specific duties, including riding warhorses, jousting, attending tournaments, holding Round Tables and hunting, as well as aspiring to the more æthereal virtues of "faith, hope, charity, justice, strength, moderation and loyalty."
Knights of the late medieval era were expected by society to maintain all these skills and many more, as outlined in Baldassare Castiglione's The Book of the Courtier, though the book's protagonist, Count Ludovico, states the "first and true profession" of the ideal courtier "must be that of arms." Chivalry, derived from the French word chevalier ('cavalier'), simultaneously denoted skilled horsemanship and military service, and these remained the primary occupations of knighthood throughout the Middle Ages.