Rocket-propelled cats and birds may have been used in 16th century warfare

Colour illustrations of rocket-propelled cats and birds have recently been found in a 16th century war manual.

Written by artillery master Franz Helm of Cologne, who likely fought against the Turks during the mid-16th century, the manual on artillery and siege warfare dates to about 1530, Discovery News reported.

Among fanciful illustrations, the text in German explains the shocking project to put timed explosives onto birds and cats in order to "set fire to a castle or city which you can't get at otherwise."

Called "Buch von den probierten Kunsten" (Book of the tested arts) Helm's treatise circulated widely in manuscript but was not published until 1625. It was rediscovered by Mitch Fraas, a historian and digital humanities expert at the Penn library.

Fraas began researching the war treatise after finding its unusual and disturbing illustrations on the book blog BibliOdyssey.