Diagrammatizing the Art of Memory. Two Examples of Tree Diagrams in Mnemonic Treatises from the 15th Century

Since the 1970s, the mnemonic nature of the medieval image has given rise to a growing historiography on visual habits, mental practices, and cultural prerequisites for understanding images. At the core of a considerable number of studies are diagrams, i.e., figures aiming at bringing at least two elements into visual connection with each other, without necessarily figuring this connection mimetically. Diagrams are designed to organize material, but are also useful to inscribe material in the memory. In Western and Central Europe, from the 13th century onwards, this dual function expresses a growing need to order mental activity. It echoed the intensive production of organizational media to understand the world and disseminate knowledge. Medieval diagrams are the result of the spread of mnemotechnics, but they have even encouraged this spread. However, in the history of the links between arts of memory and diagrams, a point still needs to be highlighted, probably because it concerns the materiality of the writings of art of memory, while texts referring to this art or recommending its practice are not always translated or even transcribed. This point is the way diagrams are used in these texts, not (or not only) as examples of tools that the reader/viewer can reuse for its own purpose, but as tools to organize the mnemotechnic rules themselves. This paper focuses on the most common diagram in the Middle Ages, the tree diagram. It examines two rare examples of treatises using tree diagrams to modelize the divisiones of rules for the mnemotechnic activity, thus constituting propaedeutic and heuristic tools for learning the art of memory itself.