One night in Deventer, in the Netherlands, around 1420, a cat got into a scriptorium and urinated on an unfinished manuscript.

We know this because the scribe did not start the page over. Parchment cost too much for that. Instead he left the ruined section blank, drew a small pointing hand — the medieval equivalent of a sticky note — added a sketch of a cat, and wrote, in Latin, a formal complaint to posterity: "Here is nothing missing, but a cat urinated on this during a certain night. Cursed be the pesty cat that urinated over this book during the night in Deventer, and because of it many others too. And beware well not to leave open books at night where cats can come."

The manuscript survives, stain and curse and all, in the city archive of Cologne. The cat has been dead for six centuries. The complaint about the cat is now older than most nations, and it is still doing its job, because here you are, being warned.

In my last post I argued that monastic copying was infrastructure — a deliberately engineered redundancy network that carried nearly everything we have of the ancient world across a thousand-year gap. That post was about the system. This one is about the workforce, because the margins of the manuscripts preserve something the system never intended to transmit: the voices of the people running it. And what those voices mostly say is that the work was slow, the room was cold, the parchment was bad, and the cat was a menace.

The complaint department

A scribe's output ran to roughly three or four pages a day, in the perhaps six hours of usable daylight the work allowed — many houses banned candles in the scriptorium, for the sensible reason that the room was full of the only copies of things. In winter the pace dropped further, because quills have to be held in fingers and fingers freeze.

The scribes told us all of this themselves, in colophons — the little notes at the end of a finished text where the copyist was allowed, briefly, to exist. Thousands survive, and as a genre they are less "soli Deo gloria" than you'd hope and more like the comment section of a man at the end of a long shift. The ink is thin. The parchment is hairy — an actual recurring complaint; badly prepared skin kept its follicle stubble, and the pen snagged on it. The day is dark. My hand hurts. I am very cold.

The most honest colophon in the entire corpus is preserved in a manuscript at Trinity College, Cambridge, and it scans like a drinking song, because it may have been one: Explicit hoc totum, pro Christo da mihi potum — "The whole thing is finished; for Christ's sake give me a drink."

And the fullest statement of working conditions comes from a monk named Florentius of Valeránica, writing in Castile in the tenth century, who wanted future readers to understand exactly what a book cost the body that made it: the labor "mists the eyes, it curves the back, it breaks the belly and the ribs, it fills the kidneys with pain, and the body with all kinds of suffering." He follows it with a plea to handle the book gently, because a careless reader, he says, destroys a manuscript the way hail destroys a field. That's not a metaphor a man reaches for unless he has watched both happen.

Sit with the economics of that complaint for a second. Roughly three-quarters of the cost of a medieval book was the labor of the man writing it. The kidneys were the expensive part.

The cats were not helping

The Deventer cat is not an isolated incident; it's just the best-documented crime. In the state archives of Dubrovnik there is a page from a government letter-book — the entry is dated March 11, 1445 — bearing a diagonal line of inky paw prints, where a cat evidently stepped in the ink pot first and then walked across the freshly written page with what one has to assume was total indifference. A historian noticed the prints in 2011, and the photograph promptly went further around the world than most peer-reviewed findings ever do.

But the cats weren't only vandals, and the proof is the most charming thing the whole monastic diaspora ever produced. Sometime in the ninth century, an Irish monk working far from home — at or near the abbey of Reichenau, on a lake island in what is now southern Germany — filled a personal notebook with grammar notes, astronomy, and, in the margins of his own language, a short poem about working alongside his white cat. The poem is called "Pangur Bán," after the cat, and its conceit is that master and animal are in the same trade: Pangur hunts mice, the monk hunts words; each sits patiently for hours; each rejoices when something is caught.

The physical object tells you the rest. An Irish-language poem, composed at a German monastery, survives today in an abbey in Austria — one man's homesickness, riding the same network that was carrying Augustine and Tacitus, with a cat purring through the middle of it. It is probably the most beloved thing ever written in Old Irish, and it was written in a notebook nobody was ever supposed to read.

Curses as a security system

The scribes knew better than anyone what a book cost, which is why the era's version of anti-theft technology was the written curse. The logic was airtight for its time: a book took months of a man's eyes and back to make, it could be carried off under one arm, and the only lock that traveled with it was God.

So they wrote anathemas into the flyleaves, and some are magnificent. The Arnstein Bible, made in Germany around 1172 and now in the British Library, closes with a curse on any future thief that escalates like a man warming to his subject: may he die, may he be roasted in a frying pan, may the falling sickness and fever attack him, and may he be broken on the wheel and hanged. Amen.

One caution, because this corner of history is infested with fakes: the most-quoted "medieval" book curse on the internet — the one where the stolen book turns into a serpent in the thief's hand and bookworms gnaw his entrails, usually attributed to a monastery in Barcelona — is a hoax, invented in 1909 by an American librarian named Edmund Pearson for a fake almanac. It's a good curse. A librarian wrote it. Just not a medieval one. The real ones, frying pan and all, are better anyway, because a real man wrote them about a real fear: that the thing he had traded his eyesight for would walk out the door.

Why this matters for the novel

The Aethelred Cipher opens in a Rhineland monastery in 1347, and I wrote it knowing that the historical people in that room were the people in these margins — men with aching hands and strong opinions about parchment quality, who complained their way through the most consequential clerical work in European history without ever quite knowing that's what it was. The grand version of their story, the one I told in the last post, is that they were nodes in a network that backed up a civilization. The version they'd have recognized is: the ink was bad, the light was going, Compline was soon, and something had walked across the page.

Both versions are true. That's the thing about the manuscripts: they carried the texts, and in the margins, by accident, they carried the people. The system was designed to make the copyists invisible — perfect transmission, nothing added. What actually survived is Tacitus, Augustine, the Rule of Benedict, and one Irishman's cat, whose name we still know: Pangur Bán, the white one, dead these eleven hundred years, immortal because his human liked having him around.

The Arnstein Bible made it, by the way — intact, frying-pan curse and all. It's in the British Library now, where you can go and read the threat yourself, eight and a half centuries after a scribe decided his year of labor was worth defending forever.