Franz Helm

Described as a "shooter, cannonier and fireworker,"[2] Helm fought with the armies of the Holy Roman Emperor Charles V against the Ottoman Empire.

Whether it had any practical influence on the duke's army is unclear but it is possible that the later construction of the royal armoury at Munich's Marstallplatz followed Helm's recommendations.

[5] One method described by Helm has attracted attention for its illustration of what has been dubbed a 'rocket cat' – a feline with what appears to be a rocket on its back propelling it towards a castle or fortified town.

[5] He writes: 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.

"[6] Helm was not the first to propose or use incendiary animals; the Biblical figure Samson is described as attaching torches to the tails of three hundred foxes, leaving the panicked beasts to run through the fields of the Philistines, burning all in their wake.

[7] Early Sanskrit texts, early Scandinavian sources and the Primary Chronicle mention cats and birds bearing incendiary devices,[8] while the 10th century Chinese manual Hu Chhien Ching and its 11th century successor Wu Ching Tsung Yao describe and illustrate a series of "fire animals".

These include "apricot-stone fire sparrows" carrying burning tinders attached to their legs inside an apricot stone, with the hope that they would fly into the enemy's granaries and set them on fire, and "magic-fire flying crows", artificial birds powered by four rocket tubes.