It is a commonplace that Chaucer's genius lay in his seemingly infinite capacity to adapt stories and forms to serve his particular purposes. In his work readers constantly hear multiple echoes and perceive shadowy antecedents. His sources are often identifiable but so altered by his imagination as to function as analogues, as the well-known relationship of Chaucer's Troilus to his source in Boccaccio's Il Filostrato demonstrates. In the same way that the Troilus adapts and renovates Filostrato, Chaucer's Legend is paradoxically both derivative and an original conception. It is a singular adaptation of a series of narratives which appear as a group in early humanist writing, examples drawn specifically from the classical tradition to exemplify behavior in the secular world. Early humanism authorized collections of exemplary narratives under the aegis of providing moral instruction for the aristocracy. Petrarch's Illustrious Men, followed by Boccaccio's Illustrious Men and Famous Women are prime examples. Within this broad template of exemplary narratives, several major late medieval European writers – Machaut, Boccaccio, Christine de Pizan, Gower and Chaucer – adapt classical stories of women, imbuing them with various thematic foci to illustrate the particular point each wants to make. Their combined work demonstrates the adaptability of the trope of women's fidelity to exemplify a variety of social and ethical issues.