Proof that gun powder technology captured the imagination of 16th century military minds can be found in a manual written by artillery master Franz Helm of Cologne, Germany who proposed strapping rockets to the backs of cats in order to "set fire to a castle or city which you can't get at otherwise." (photos)
The illustrated manual from around 1513 suggested, "Create a small sack like a fire-arrow. If you would like to get at a town or castle, seek to obtain a cat from that place. And bind the sack to the back of the cat, ignite it, let it glow well and thereafter let the cat go, so it runs to the nearest castle or town, and out of fear it thinks to hide itself where it ends up in barn hay or straw it will be ignited."