What is Greek Fire?
Greek fire or ‘liquid fire’ is a well-known piece of incendiary technology used by Byzantine military forces to burn their enemies alive or set ablaze rival ships. The devices used were akin to a modern flamethrower and we find from our sources that these flamethrowers-like weapons were placed upon Byzantine warships or used in a smaller format as hand-held devices.
The weapon’s ingredients are still debated and there is yet, or unlikely to be, a definite answer by modern scholars. Due to the success of the weapon, the Byzantines were avid to keep its recipe a secret, however Roland argues that its secret was even lost to the Byzantines at a relatively early stage due to its stressed secrecy. In September 2002, John Haldon (Byzantine historian) attempted to reconstruct the device and provided some interesting thoughts on its use. A reconstruction of the experiment can be found below.
Theophanes Confessor notes that Greek fire was designed in the 670s by an architect named Kallinikos, who had come to Constantinople as refugee from Heliopolis, Syria. The Greek fire he created would end up being used against his Arab conquerors, alongside other foes on several occasions. The most notable occurrences of Greek fire were in the defence of the capital, Constantinople.
The Capital Under Siege: The Use of Greek Fire
From a variety of contemporary accounts, we find several appearances of Greek fire used to defend Constantinople, with notable examples being the Arab sieges of Constantinople in AD 674-678 and 717/718, alongside later defences against the Rus in the Tenth Century. The picture from our primary sources is chaos and destruction. Luitprand of Cremona comments that during the Rus siege of AD 941: “The Rus’, seeing the flames, jumped overboard, preferring water to fire. Some sank, weighed down by the weight of their breastplates and helmets; others caught fire.” Theophanes provides a similar depiction during the Arab siege in AD 674-78 and comments: “…the Romans…manufactured a naval fire with which he kindled the ships of the Arabs and burnt them with their crews.” It can be argued that not only was Greek fire destructive in its damage output, but it was also a significant tool for physiological warfare.
While Greek fire is often depicted as being successful, Nikephoros I (Patriarch of Constantinople) also narrates the Arab siege of Constantinople in AD 674-78 and does not recount the use of Greek fire, and therefore does not present it as the decisive asset as Theophanes does.
Although Greek fire was believed to be a significant military asset, it was not the only one in the Byzantine arsenal. In AD 626, Constantinople was besieged by a combined force of Avars and Sasanians. At this point, the Byzantines had not discovered Greek fire, and so we find success originating from military virtue, their devotion to the Virgin Mary, and events that occurred further afield.
Overall, Greek fire was an important part of the Byzantine military arsenal, however, it should be remembered that other means and methods of defeating its enemies were still influential in the outcome of battle.
*Note* This is an example blog post for my Medieval Worlds UG seminar group and their upcoming assessment.
 For a contemporary passage on the projection of Greek fire on ships, see Anna Komnena, Alexiad. XI. 10 – “…on the prow of each ship he had a head fixed of a lion or other land-animal, made in brass or iron with the mouth open and then gilded over, so that their mere aspect was terrifying. And the fire which was to be directed against the enemy through tubes he made to pass through the mouths of the beasts, so that it seemed as if the lions and the other similar monsters were vomiting the fire.” For the use of hand-held projectors, see Pryor and Jeffreys (2006), pp. 617-619.
 The most updated hypothesis on Greek fire ingredients is Haldon (2006), with an earlier and problematic study undertaken by Pászthory (1986).
 Roland (1992), pp. 662-671.
 Haldon (2006), 290-325.
 Theoph. Chronographia. AM 6165.
 Ellis-Davidson (1973), pp. 61-74.
 Gregory (2010), pp. 185, 200, 257-258.
 Luitprand of Cremona, Antapodosis. V. 15.
 Theoph. Chronographia. AM 6165.
 Nikephoros. Short History. 34. Nikephoros was not afraid to state the successfulness of Greek fire later in his account. During the Arab siege of AD 717/718, Nikephoros narrates the impact it had on breaking the Arab morale during the siege [ibid. Short History. 54.].
 Chron Pasch. Olmpiad 351 .
 For a recent study of the siege, see Hurbanic (2019).
Anna Komnena, Alexiad, trans. E.R.A. Sewter (London, 2009).
Chronicon Paschale, 284-628, trans. M. Whitby and M. Whitby (Liverpool, 2007).
Luitprand of Cremona, Antapodosis, trans. F.A. Wright (London, 1930).
Nikephoros I Patriarch of Constantinople, Short History, trans. C. Mango (Washington D.C, 1990).
Theophanes Confessor, Chronographia, trans. C. Mango and R. Scott (Oxford, 2006).
Ellis-Davidson, H. R, ‘The Secret Weapon of Byzantium’, Byzantinische Zeitschrift 66 (1973), 61-74.
Gregory, T.E, A History of Byzantium [Second Edition] (Chichester, 2010).
Haldon, J, “Greek Fire” Revisited: Current and Recent Research’, in E. Jeffreys (ed.), Byzantine Style, Religion and Civilization: In Honour of Sir Steven Runciman (Cambridge, 2006), 290-325.
Haldon, J, Warfare, State and Society in the Byzantine World 565-1204 (London and New York, 1999).
Harris, J, Introduction to Byzantium, 602-1453 (London and New York, 2020).
Hurbanic, M, The Avar Siege of Constantinople in 626: History and Legend (Cham, 2019).
Pászthory, E,‘Über das ‘Griechische Feuer’. Die Analyse eines spätantiken Waffensystems’, Antike Welt, 17.2 (1986) 27–38.
Pryor, J and Jeffreys, E, The Age of the ΔΡΟΜΩΝ: The Byzantine Navy ca 500-1204 (Leiden, 2006).
Roland, A, ‘Secrecy, Technology, and War: Greek Fire and the Defence of Byzantium, 678-1204’, Technology and Culture 33.4 (1992), 655-679.