Why Does This 14th Century Book Have A Dial In The Cover?

Oh, my…the bunny trails we do chase here at Grailrunner for your entertainment!

I’ve got a crazy one for you today: a 14th century copy of an 11th century book called The Experimentarius by Bernardus Silvestris of Tours that he had virtually nothing to do with, that is nowhere titled like that, that played a desperate role in a terrifying city siege, and that has a funky set of cogged wheels embedded in its cover.

Welcome to the Inspirations From History series!

I’ll define my terms shortly and explain all this, and provide you some fascinating links, but let me tell you how I came across this intriguing bit of historical curiosity. I was writing this article here about a 13th century geomantic machine and saw something in the footnotes of a 2003 study by Emilie Savage-Smith and Marion B. Smith (follow the link for a download option). I’m a sucker for little nuggets in footnotes buried in dense books. If you’ve never read Jorge Luis Borges, he does that in some of his fiction.

Anyway, here’s what I read:

“The Oxford, Bodleian Library, Western Manuscripts, MS Digby 46, a fourteenth-century copy of The Experimentarius, has set into the inside front cover of the volume two interlocking wooden cogged wheels with twenty eight and thirteen teeth, by which one can find a random number, rather than by counting random points.”

And I thought…huh? Why in the world would I need a random number reading a book? What’s it for? And how cool does it look? And can you play Dungeons & Dragons with it?

Once I started chasing details on this little marvel, I realized quickly the scarcity of information available about it. I did however find a deep dive article written by Dr. Charles Burnett in 1977, who’s still teaching at the Warburg Institute in London (but who hasn’t unfortunately responded to an interview request). He specializes in the transmission of texts, techniques and artifacts from the Arab world to the West, especially in the Middle Ages.

Here’s a link to the article I’m talking about, titled What Is The Experimentarius? It’s behind a paywall unless you have some connection to a recognized university, but it really offers a wealth of history and analysis on the book in question and is the source of much of what I say here.

Who was Bernardus Silvestris?

Bernardus Silvestris was a 12th century philosopher (and scientist, I guess, though that whole thing back then was a bit of a blur) who wrote an influential poem called Cosmographia that supposedly inspired people to feel good about exploring metaphysics and science with allegories. Anyway, Dr. Burnett effectively swats away any notion that Silvestris wrote any substantial portions of the book we’re discussing today, so let’s not dwell on him. We’ll have to find peace with the idea that the author is unknown.

What’s this book about?

We’ll also have to recognize that big portions of the book in question are a bit irrelevant for our purposes here today, as its varied copies in various museums around the world bear somewhat different content and don’t all matter for those weird wheels or their function. No, the main event here is a subset of the book that Dr. Burnett prefers to name Sortes Regis Amalrici, meaning “The Lots Of King Amalric”.

Why that name?

Sortes literature was a long-standing means of using various mechanisms to produce random numbers (like dice or random pokes in sand), forcing some pseudoscientific-looking ritual involving bouncing around tables, and ultimately selecting from a wide set of verses an oracle answer to whatever question a seeker was asking.

It’s a tradition going all the way back to ancient Greece, and continued for well over a thousand years. You can find the full translated text of the most famous of these ancient sortes texts, titled The Oracles of Astrampsychus in the Anthology of Greek Popular Literature by William Hansen.

So it’s a 14th century copy of a 12th century book for telling the future?

Yes it is. And I became terribly interested in understanding what manner of questions and concerns these seekers would have to ask such a book, given their belief that this secret tome had unlocked a means of resonating with the very day and time of their consultation, and the crystal spheres inside which they lived, to reveal the secrets of the universe.

So I used Google Translate to convert the functional tables from Latin in Burnett’s article to experience how this all worked. I included that and the instructions on the book’s usage in a spreadsheet, which I’m including at this link here.

Where can I see the original parchment pages of this book?

You can go to the Bodleian Library site here or to the British Library site here to take a luxurious look if you (like me) see the joy of perusing high resolution images of super old parchment documents and the little doodling pics in the margins like these:

Here is a reproduction of tables 1 through 4, which are the ones I translated in the Excel document linked above:

Don’t make me read all that, how did this book work?

Determine a random number, either through geomantic points or a dial like the one on our cover in question. Spin it or close your eyes and start turning, then peek to see what you got.

If the random number exceeds 7 (say 10), find the theme of the question on table 1 (say “about war”) and count that as 7. Move up the table till you hit your number (in this case, move 3 up to “about wishes”). Then follow table 1 instructions (“western face of the tower of Jupiter”) -> table 2 instructions (“13th day of the Moon”) -> table 3 instructions (“18th moon”) -> table 4  Judge (“Alchozean”)

Each Judge has verses, and you add 9 (a constant) to your random number to select the relevant verse which is your oracle. (So in this case, verse 19).

If the random number is exactly seven, then follow the tables as above but begin directly from the theme of the question (“about war”). The oracle will be the verse for the respective Judge numbered 7 + 9 = 16.

If the random number is less than 7 (say 5), then count the theme of the question as the random number (so 5 in this example) then go down the table till you reach 7 (“southern face of the tower of Mars”).

Let’s keep in mind here that the point of all that jumping around and Middle Ages tech-speak is to make this seem like science. It’s possible seekers could only finish their consultations in many cases on the actual days listed in these tables, which would really make it all seem super serious.

Where the heck are the Judge verses?! I wanted to play Dungeons & Dragons with this thing!

I hear you, and that’s totally what I was going to do. I wanted to see if I could use an ancient fortune-telling book to act as dungeon master for a solo roleplaying game. Would have been awesome. However, Burnett didn’t include the Judge verses in his appendices, and the Latin font in the originals I could find was incomprehensible to me. I couldn’t even make out what letters they were. Was hoping Burnett would provide originals so I could translate them, but no luck.

Well, what kinds of questions did people ask with this book?

Ahhh…that was super interesting to me. Take a look at Table 1 to see what issues concerned these folks. Some of these are very telling of the times (“about prison”, “about hope”, “about a dream”, “about a foreigner”) but practically all of them are common to all of us and incredibly easy to understand why they concerned the book’s users a thousand years ago.

One curiosity here: number 25’s original Latin is clear on the parchment and reads “egro” which translates as “in the desert”. I strained to see why anybody had questions relating to the desert (though my imagination wandered) till I realized they probably slipped and meant “agro” which means “the field”, or crops probably. Yeah, that’s more likely by a mile.

What was that bit you said earlier about a terrifying city siege?

I’ll leave you with this story, this glimpse of what the Sortes Regis Amalrici and these weird little tables meant to some extremely frightened people in a terrible time. It’s an excerpt from a book written in the late 1200’s by Rolandino Patavino, a notary who worked in the Italian city of Padua.

The background is that Padua was on the rise and set to be as big a deal as Venice back in the day before Italy was a thing. Twenty years before, the Holy Roman Empire had taken and held Padua up until 1256 when some exiles (supported by the Pope) took it back. That lasted a year until the villain and tyrant of the story (named Ezzelino) laid siege to Padua to return it to the hands of the Holy Roman Empire.

Here’s what Patavino recounted of those days trapped and surrounded by a returning conqueror and likely wondering whether they would all be slaughtered or would starve to death inside the city walls:

“Some of the prisoners anxiously searched through the lots to find when the army was to arrive. And one of the points of a certain art…is to say that Padua could not be captured in these times. Another one of the prisoners favored this, saying, “Examine the book carefully.”

That’s our book he’s talking about. They were desperately flipping through those very pages to find hope of salvation. And it was right.


That’s what I wanted to bring you this time. I hope you found it diverting like I did. Let me know what you think. And till next time,