Creating a book in the Middle Ages was no small feat: A scribe or a copyist would labour for months and even years, meticulously forming each letter by hand, using only natural light. Bereft of any comfort like a standing desk, a soft seat, or any semblance of proper lumbar support, those wordsmiths saw their bodies gradually deform and break down, all in the name of ensuring the survival of the written word.
Because of the tremendous effort it took to create a book in those times, scribes and book aficionados went to great lengths protecting each precious manuscript, harnessing the power of the word and creating some of the most powerful, damning curses ever composed by a human mind.
Being excommunicated, though not too scary to a modern man, was a dreadful threat in the Middle Ages, and it only went worse from there. A book thief could expect to be sliced in half lengthwise by a daemon's sword, have both his hands chopped off, and spend eternity into hell's seas of fire and brimstone.
Excommunication, or anathema, often took the form of a short rhyming couplet like,
"May the sword of anathema slay
Whoever steals this book away."
Many curses, however, went into much greater detail and focused on the potential physical anguish awaiting book thieves. The individual scribe's own imagination was the only limit to the gruesome intricacies of torture. A sample death curse may read:
"If anyone takes away this book, let him die the death; let him be fried in a pan; let the falling sickness and fever seize him; let him be broken on the wheel, and hanged. Amen."
Some curses were even more elaborate and vivid:
"For him that stealeth, or borroweth and returneth not, this book from its owner, let it change into a serpent in his hand & rend him. Let him be struck with palsy & all his members blasted. Let him languish in pain crying aloud for mercy, & let there be no surcease to his agony till he sing in dissolution. Let bookworms gnaw his entrails in token of the Worm that dieth not, & when at last he goeth to his final punishment, let the flames of Hell consume him for ever."
There is a garden variety of such terrifyingly specific curses. There is also evidence of phrases and even full death scenarios repeating across books, which suggests that the same scribe penned them, that scribes exchanged particularly potent curses, or that they paid homage to one another's morbid creativity by borrowing snippets of it.
If you feel inspired to protect your own library with a good, solid Medieval curse, try this one for size:
"May whoever steals or alienates this book, or mutilates it, be cut off from the body of the church and held as a thing accursed."
If the subject of Medieval book curses intrigues you further, you should get a copy of Marc Drogin's "Anathema! Medieval Scribes and the History of Book Curses", a comprehensive compendium of lugubrious incantations and excommunications which spans centuries of internationally sourced prime cuts on the subject. He purportedly has enough new material for a second edition, too, so be on the lookout and, for your own sake, don't ever steal a book!