The Ars Notoria is one of the stranger texts of the Latin Middle Ages. It appears in manuscripts from the early thirteenth century, is attributed to Solomon, and promises mastery of the liberal arts, philosophy, and theology to anyone who recites its prayers (some in Latin, some in unintelligible "words") while contemplating diagrams called notae, under a strict regimen of fasting and prescribed days.

What I find interesting is how seriously it was taken. Thomas Aquinas addressed it by name in the Summa (II-II, q. 96, a. 1) and ruled it illicit. In the fourteenth century, the monk John of Morigny wrote his Liber florum partly because he had practiced the notory art and come to fear it. The standard critical edition is Julien Véronèse's L'Ars notoria au Moyen Âge (2007), for anyone who wants the texts rather than the rumors.

Has anyone here worked with the notae themselves, or with the later Ars Notoria printed in Robert Turner's 1657 English translation, which differs considerably from the medieval versions?

(Disclosure: I write fiction that uses this material. I put together a plain-history note on it here.)