- The Ars notoria was a medieval magical manuscript that promised to rapidly transmit advanced knowledge through diagrams, incantations, and rituals.
- Its diagrams functioned like religious icons, allowing direct contact with supernatural forces, and were combined with prayers and mysterious words.
- The text was condemned by theologians like St. Thomas Aquinas as unlawful and demonic, yet it remained popular and was copied in religious institutions.
- John of Morigny, a 14th-century monk, documented his dangerous experiences with the Ars notoria, realizing it invoked demons despite its pious appearance.