⏱️ Lectura: 10 min
A manuscript copied at least 56 times across medieval Europe promised something that sounds familiar today: knowing everything without years of study. All it took was memorizing complex diagrams and reciting words in a precise order. The essay by historian Anne Lawrence-Mathers, published on July 29, 2026 in The Public Domain Review, reconstructs the history of the Ars Notoria: the magical treatise that, eight centuries before generative artificial intelligence, was already selling the fantasy of instant knowledge.
📑 En este artículo
The promise wasn’t technical but spiritual: direct contact with angels through images and prayers. The Church condemned it, but the text survived, was translated, and even reached the printing press.
TL;DR
- The Ars Notoria is an anonymous 13th-century magical treatise that promised to transmit all university knowledge without years of study.
- 56 complete manuscripts of the text survive, according to the essay by Anne Lawrence-Mathers published on July 29, 2026 in The Public Domain Review.
- Thomas Aquinas condemned it in Question 96 of the Second Part of his Summa Theologiae, calling it illicit and useless.
- The oldest known manuscript copy is held at Yale University Library and is believed to have been produced in the milieu of the University of Bologna.
- The text is falsely attributed to King Solomon, to whom an angel supposedly delivered it during a night prayer.
- Unlike other magical texts, its diagrams don’t illustrate content: they function as religious icons for direct contact with the supernatural.
- Despite ecclesiastical condemnation, it was copied in religious institutions until the end of the Middle Ages and later translated and printed.
What happened with the Ars Notoria
The Public Domain Review, a magazine dedicated to rescuing public domain works, published an extensive essay on the Ars Notoria on July 29, 2026, written by Anne Lawrence-Mathers, a historian specializing in medieval magic and science. The text reconstructs the origin, use, and ecclesiastical persecution of a treatise that circulated in European universities from the 13th century onward, promising to transmit, all at once, all the knowledge then taught in the faculties: grammar, logic, arithmetic, geometry, astronomy, and theology.
The essay is part of a series the magazine titled, with barely concealed irony, Artificial Intelligence: it examines how different cultures imagined shortcuts to knowledge before computing existed. The Ars Notoria is, in that sense, the most elaborate case. It doesn’t promise a magical object or an improvised ritual, but a complete system of diagrams, prayers, and temporal sequences that the practitioner had to follow precisely, almost like someone following a technical protocol step by step.
Context and history
The text is documented from the 13th century onward and is presented as an angelic revelation delivered to King Solomon during a night prayer, an attribution that gave it religious legitimacy compared to other magical texts clearly at odds with the Church. The oldest known manuscript copy is now held at Yale University Library and, according to the essay, everything suggests it was produced in the milieu of the University of Bologna, likely for a university master with prior experience using the treatise.
Saint Thomas Aquinas devoted an entire question of his Summa Theologiae to it (Second Part, Question 96), one of the most authoritative summaries of Christian doctrine. His conclusion was blunt: the Ars Notoria is “illicit and useless.” Useless because it cannot deliver what it promises; illicit because its signs, not being understood by humans nor sent by God like the sacraments, are exactly the kind of object that opens the door to dealing with demons. Other major theologians repeated the objection, but the Church never managed to, nor does it seem to have had much interest in, eradicating it: it kept being copied and preserved in religious institutions until the end of the Middle Ages, and in the early modern period it was translated and even reached the printing press.
Technical details and performance
What sets the Ars Notoria apart from other medieval magic manuals is that its diagrams don’t illustrate anything: they aren’t a drawing of the content they teach, nor a model for building a ritual object. They function more like religious icons, images whose faithful contemplation alone, combined with correct recitation, opens a channel of contact with benign supernatural forces. Each figure combines geometric shapes, patterns, and “words” that are mostly combinations of unintelligible letters, presented as angelic names in Greek, Hebrew, or “Chaldean.”
Its use required following a strict sequence: a protective prayer before starting, contemplation of the corresponding diagram, recitation of the assigned prayer, and, in many cases, repeating the cycle over several days according to a calendar and a cardinal-point orientation. The very order in which the passages had to be used wasn’t always obvious, and even the correct pronunciation of the names was a source of concern for the practitioner.
flowchart TD
A["Initial protective prayer"] --> B["Contemplate the diagram"]
B --> C["Recite the assigned prayer"]
C --> D{"Was the day's sequence completed?"}
D -->|"No"| B
D -->|"Yes"| E["Repeat the next day according to the calendar"]
E --> F["Promised knowledge (never verified)"]
Today, that same manuscript can be viewed without traveling to Paris thanks to the IIIF (International Image Interoperability Framework) protocol, an open standard that many university and national libraries use to expose their digitized collections through a common API. To confirm that a digital library resource supports IIIF, simply check the image’s info.json endpoint and review the profile field, which indicates the level of conformance with the standard’s Image API.
How to try it
You don’t need to be a historian to explore a digitized manuscript programmatically. Any IIIF-compatible library exposes a JSON manifest listing the pages, and that manifest can be queried the same way from Windows, macOS, or Linux.
# Linux / macOS (bash)
curl -s "https://ejemplo-biblioteca.org/iiif/2/MANIFEST_ID/manifest.json" | jq '.label'
# Windows (PowerShell)
Invoke-RestMethod "https://ejemplo-biblioteca.org/iiif/2/MANIFEST_ID/manifest.json" | Select-Object -ExpandProperty labelThat first command only requests the manifest’s title: it’s useful for confirming that the library responds and that the manifest URL is correct before writing any code.
For something more realistic, a Node.js script walks through the manifest’s pages and lists the available images. Node runs the same way on all three operating systems, so the script doesn’t change between Windows, macOS, and Linux, only the way it’s installed:
# macOS (Homebrew)
brew install node
# Linux (Debian/Ubuntu)
sudo apt install nodejs npm
# Windows (winget)
winget install OpenJS.NodeJS// list-iiif-pages.js
import fetch from "node-fetch";
const manifestUrl = process.argv[2];
const res = await fetch(manifestUrl);
const manifest = await res.json();
const canvases = manifest.items ?? manifest.sequences?.[0]?.canvases ?? [];
console.log(`Title: ${manifest.label?.en?.[0] ?? manifest.label}`);
console.log(`Pages found: ${canvases.length}`);
canvases.slice(0, 5).forEach((canvas, i) => {
console.log(`Page ${i + 1}: ${canvas.id ?? canvas["@id"]}`);
});Run with node list-iiif-pages.js MANIFEST_URL, the script prints the manuscript’s title and the first five pages with their image identifier, ready to pass to a viewer like Mirador or OpenSeadragon.
Impact and analysis
💭 Key point: The Ars Notoria didn’t promise new information, it promised skipping the effort of learning it: contemplate a diagram and recite a prayer instead of years of study. That same fantasy, skipping the practice, is what much of generative AI marketing sells today.
The comparison isn’t just an editorial flourish. The parallel shows up in how both promises are presented: a closed system, with its own vocabulary, that guarantees skipping the slow process of acquiring a skill. The table below summarizes where the analogy holds and where it breaks down.
| Aspect | Ars Notoria (13th century) | Generative AI marketing (2026) |
|---|---|---|
| Central promise | Complete knowledge without years of university study | Expert mastery of a topic in minutes or hours |
| Mechanism | Contemplating diagrams and reciting prayers in precise order | Writing a prompt or following a crash course |
| Source of authority | Angels and a false attribution to King Solomon | Benchmarks, demos, and user testimonials |
| Main criticism | Thomas Aquinas: “illicit and useless” in the Summa Theologiae | Studies documenting loss of comprehension when delegating tasks |
| Outcome | Survived as a clandestine practice, never proven effective | Useful tool with known limits, not a substitute for practice |
⚠️ Watch out: The comparison has a real limit: the Ars Notoria was presented as sincere religious devotion, not as a commercial product. Equating it without nuance to an AI company would be unfair to the medieval context and simplistic about the current debate over these tools.
What does become clear reading Aquinas eight centuries later is that the core argument of his critique still holds without changing a word: a system that promises results without the user understanding the internal mechanism is, at minimum, hard to audit. That applies just as much to medieval diagrams as to a language model that generates an answer without exposing its reasoning.
What’s next
Libraries like Yale and the National Library of France continue digitizing medieval magical manuscripts and exposing them via IIIF, expanding each year the corpus available to historians and to any curious developer who wants to build a viewer or search tool over those collections. Meanwhile, the debate over how real the promise of “instant mastery” is in today’s AI tools remains open, and the evidence available so far agrees on one point: deep understanding of a skill still requires deliberate practice, with or without an assistant along the way.
📖 Summary on Telegram: View summary
Try it yourself: ask your university library for the IIIF link to any digitized manuscript and run this article’s script to list its pages in under five minutes.
Frequently Asked Questions
What is the Ars Notoria?
It’s an anonymous magical treatise, documented from the 13th century onward, that promises to transmit complete knowledge of medieval university subjects through the contemplation of diagrams and recitation of prayers in a precise order and calendar.
Why did the Church condemn it?
Saint Thomas Aquinas analyzed it in Question 96 of the Second Part of his Summa Theologiae and concluded it was “illicit and useless”: useless because it couldn’t deliver what it promised, and illicit because its signs opened the door to contact with demons.
How many copies survive today?
56 complete manuscripts survive, according to the count cited in Anne Lawrence-Mathers’s essay. The oldest known copy is held at Yale University Library.
What relation does it have to today’s artificial intelligence?
No technical relation: the Ars Notoria is ritual magic, not computation. The relation is cultural, both sell the fantasy of accessing expert knowledge without going through the process of learning it.
What is the IIIF protocol and why does it matter to a developer?
It’s an open standard that lets you query images of digitized manuscripts from any compatible library through the same API, without depending on each institution’s proprietary viewer.
Where can the original essay be read?
The complete essay, with images of the manuscripts cited, is published at The Public Domain Review.
References
- The Public Domain Review: “Artificial Intelligence: Ars Notoria and the Promise of Instant Knowledge”: original essay by Anne Lawrence-Mathers, the main source for this article.
- New Advent: Summa Theologiae by Thomas Aquinas: full text online, including Question 96 on superstitions and magical arts.
- International Image Interoperability Framework (IIIF): official specification of the protocol used by libraries to expose digitized manuscripts.
- Wikipedia: Ars notoria: additional encyclopedic context on the treatise and its manuscript transmission.
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Imagen destacada: Foto de Mark Rasmuson en Unsplash
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