We have specially to call attention to the two men who are throwing shells, which are probably charged with Greek fire. This invention, which inspired such terror in the Middle Ages, seems to have been discovered in the east of Europe, and to have been employed as early as the seventh century. We hear much of its use in the Crusades, by the Greeks, who early possessed the secret of its fabrication. They used it either by ejecting it through pipes to set fire to the shipping or military engines, or to annoy and kill the soldiers of the enemy; or they cast it to a distance by means of vessels charged with it affixed to javelins; or they hurled larger vessels by means of the great engines for casting stones; or they threw the fire by hand in a hand-to-hand conflict; or used hollow maces charged with it, which were broken over the person of the enemy, and the liquid fire poured down, finding its way through the crevices of his armour.
The Project Gutenberg eBook, Scenes and Characters of the Middle Ages, by Edward Lewes Cutts Published in 1911