In this paper, we will show how madness, understood through one of its medieval meanings-fol-is associated in texts and images to music, through the fol'amour, and how this notion can be analyzed in the medieval musical iconog-raphy. In order to achieve this task, we shall try to define and organize the musical iconography of the fol'amor, of the fol and its medieval social digressions -tintamarre, charivari-using the iconological methodology developed in the Musiconis project. Then, we will observe how this information can be translated into an web-based ontology in order to determine the relationships between all aforementioned elements (textual references, images, music). This exercise will help us better define the notion of madness related to music and love in the Middle Ages, as we will create an ontology that is open, flexible and reusable, associating elements from literature, visual arts and musical/poetic composition. This paper will also show how an ontology-based tool can be used in any type of scientific investigation in the humanities; and how it may be enriched using the current academic knowledge about the notion of madness, translated from all fields of the arts as well as from social, legal and medical sciences.