Note 46 — Chapter II · THE SMOOTH-BORE GUN
Reading edition
Ascribing the deliverance of Constantinople from the Saracens in the two sieges of A.D. 668 and 716 to the novelty, the terrors, and the real efficacy of Greek fire, Gibbon says: “The important secret of compounding and directing this artificial flame was imparted by Callinicus, a native of Heliopolis in Syria, who deserted from the service of the caliph to that of the emperor. The skill of a chemist and engineer was equivalent to the succour of fleets and armies.”
For the story of the manner in which its mystery was guarded at Constantinople, of its theft by the Infidel, and of the use he made of it against the Christian chivalry at the crusades, see Chapter LII of The Decline and Fall of the Roman Empire.