Hidden inside the pages of a few 16th-century manuscripts is evidence that at one time or another, warring nations at least considered using "rocket cats" as tactile weapons.
Mitch Fraas, the Schoenberg Scholar-in-Residence at the University of Pennsylvania Libraries, was pointed toward the images inside the medieval texts that show cats and birds strapped to what look to be jet packs.
"The way they're drawn it looks like they are being propelled," Fraas said. "But really they're just on fire."
Last year an Australian manuscript enthusiast who was paging through some of the 2,000 pre-1800 bounded books in Penn's collection, which are available online, found images of "rocket cats" and messaged Fraas. This led to a blog post, and then an inquiry from the British tabloid The Daily Mail.
Through translation, Fraas figured out the gist: One group is besieging a fortified town, and, "You can't inside the walls, but plenty of animals move in and out of the walls at night," Fraas said.
"Why not capture a cat or a bird or something and essentially strap a sack of gunpowder to its back, light a long fuse and let it go," he added.
The hope is if it's a dove or a homing pigeon, it returns to its home. "If it's a cat it's going to run back to its house, terrified because it's on fire," Fraas said, "And then when it reaches its resting place it will set the whole town on fire when it explodes."
But, more likely, "Once you light the fuse, the cat will run back into your tent," he added.
Nothing he read on the Austrian-Turkish wars showed evidence that cats were used as weapons. But the idea isn't new.
Russian manuscripts from the Middle Ages illustrate proposals to use birds as weapons. In the Bible, in the Book of Judges, Samson lights fox tails on fire and sets them loose.
"It seems it's an idea that people have; whether anyone actually tried it successfully I don't know," Fraas said. "I can't imagine it would work."