This article analyzes Watriquet de Couvin’s Li Mireoirs as dames [1324], focusing on the construction of the allegorical character Dame Biauté, the object of the hero’s resp. the narrator’s quest. Particular attention is paid to the didactic exploitation of allegory in the formation and explanation of abstract concepts, which serve to define Watriquet’s ideal conception of beauty. The reflection hypothesizes that the hero’s discovery of the character of Beauty contributes, for instructive purposes to a reconceptualization of the French society’s concept of beauty at that time. In this sense, the figure of Beauty serves to construct an ethics directed to the female audience. To this end, Dame Biauté is orchestrated like a mirror that presents an exemplary ideal to which the recipients are meant to model themselves. The aim of the article is to use the concept of perfect beauty as an example to illustrate the potential of allegory, emphasise its link to analogical thinking, and to show how fixed concepts can be expanded and rethought by means of rhetorical devices such as allegory.