Before the advent of bookplates, When losing a book to theft, it might seem extreme to suggest death to whoever stole it (is it though?) but that's exactly what medieval scribes did! 'Book curses' were ways scribes could invoke the wrath of God or death to dissuade people from stealing books. As books dating prior to the invention of the printing press were incredibly costly and laborious to produce, scribes would write a few lines in the front suggesting all sorts of pain and suffering that could befall would-be thieves.
One such book curse is from the Arnstein Bible, written in Germany around 1172 (pictured). It reads:
"If anyone steals it, may he die, may he be roasted in a frying pan, may the falling sickness [epilepsy] and fever attack him, may he be rotated [on the breaking wheel] and hanged. Amen."
If you'd like to learn more about book curses Marc Drogin's 'Anathema!: Medieval Scribes and the History of Book Curses' is a fabulous collection.