By Emilia Wellesley · Published May 1, 2024 · Updated May 13, 2026
Last reviewed: May 1, 2024.
What Was Greek Fire?
Greek fire was a Byzantine incendiary weapon, deployed at sea from the late seventh century onward, that burned on water, clung to wood and flesh, and could be extinguished only with great difficulty. The Byzantines projected it from bronze siphons mounted on warships, used it in hand grenades, and guarded its recipe so closely that the formula did not survive the fall of the empire.
Few weapons in pre-modern history are remembered with the specificity reserved for Greek fire. Constantinople‘s chroniclers describe its noise, its smell, its spreading orange sheet on the surface of the Bosporus. Modern chemists have proposed half a dozen mutually incompatible reconstructions of what it actually was, none of them confirmed by surviving evidence. The most honest scholarly position is the one Alex Roland set out in 1992: we know what Greek fire did, we know roughly when it appeared, and we do not know what it was made of.
This piece walks through the weapon’s emergence under Constantine IV, its decisive use against the Arab siege of 717-718, the technical apparatus that delivered it, the competing chemical reconstructions, and the question of how a working military technology was forgotten so completely. For readers tracing the broader landscape of historical and archaeological mysteries, Greek fire sits at the intersection of military history, archival reconstruction, and the chemistry of secrecy.
Kallinikos and the Invention at Constantinople
The conventional origin story places the invention with a Greek-speaking refugee named Kallinikos (or Callinicus), who arrived in Constantinople in the late 660s or early 670s from Heliopolis in Roman Syria. The chronicler Theophanes the Confessor (c. 758-817), writing roughly a century later, identifies Kallinikos as an architect or craftsman who brought with him a “liquid fire” capable of being projected against enemy ships [1]. The sequence of events Theophanes describes is corroborated, with variations, by the patriarch Nikephoros and by later Arab historians such as al-Tabari.
The First Recorded Use
Greek fire appears decisively in the historical record during the first Arab siege of Constantinople, which Theophanes places between 674 and 678. Arab fleets approached the sea walls of the city in successive campaigning seasons. According to the surviving Byzantine chronicles, dromons equipped with the new weapon broke the Arab naval effort, contributing to the eventual collapse of the siege. The chronology has been debated; John Haldon and Hugh Kennedy have argued that the date range may compress a more diffuse set of engagements, and that the dramatic single-siege framing reflects later narrative shaping rather than continuous warfare across four years.
The Siege of 717-718
The clearer demonstration came a generation later. The Umayyad caliph Sulayman launched a combined land and naval assault on Constantinople in August 717. Emperor Leo III met the Arab fleet on the Bosporus with siphon-equipped warships and broke it. According to Britannica’s entry on Greek fire, the Arab supply fleet from Egypt suffered defections and losses; the surviving ships were destroyed in the Sea of Marmara. The siege collapsed in August 718 after a brutal winter and the loss of perhaps 130,000 men. The political consequence was enormous: the Umayyad advance into Anatolia stalled, and Constantinople held for another seven centuries.
The Delivery System: Dromons and Siphons
The mechanical apparatus that projected Greek fire is, oddly, better understood than the substance itself. The principal vessel was the dromon, the medium-to-large Byzantine war galley. John Pryor’s reconstruction of the Byzantine navy describes the dromon as a fast bireme of roughly thirty-one to fifty meters in length, with an upper bank of oars worked from an outrigger and a lower bank from inside the hull, capable of carrying a forecastle siphon over a heated cauldron amidships [2].
The Bronze Siphon
The siphon was a bronze tube, fed from a sealed reservoir of the heated incendiary by a hand-operated pump. The Byzantines also fitted some siphons with bronze beast-head nozzles, partly as intimidation, partly to direct and shield the flame jet. The temperature and pressure of the discharge mattered: too cold, and the substance failed to ignite cleanly; too hot, and the operators risked the cauldron itself. Operating manuals such as the tenth-century Tactica of Leo VI the Wise and the Praecepta Militaria of Nikephoros II Phokas describe the equipment indirectly, with circumlocutions designed to preserve secrecy.
Hand-Held and Defensive Variants
By the tenth century, the Byzantines had also fielded a hand-projector called the cheirosiphon, attributed to Leo VI, and ceramic grenades filled with a similar substance. Excavations at Pergamon have recovered small thick-walled clay vessels of roughly the right capacity, though residue analyses have been inconclusive. The grenades were thrown over walls and into ships, suggesting ignition on contact rather than from a heated reservoir — one of the puzzles any chemical reconstruction has to resolve.
The Chemistry: What We Know, What We Suspect
The Byzantines did not write down the recipe. The political theorist Constantine VII Porphyrogenitus (905-959) explicitly told his son in De Administrando Imperio that the formula had been revealed by an angel to Constantine the Great, and that any emperor who shared it would be cursed. This is partly literary, partly a real description of compartmentalized state secrecy. The chemistry, accordingly, must be reconstructed from descriptions of behavior rather than a list of ingredients.
The Petroleum-Base Reading
The dominant modern reconstruction holds that Greek fire was a petroleum-based liquid, drawn from natural seeps along the Caspian shore (notably near Baku) and around the Black Sea. James Riddick Partington’s 1960 study A History of Greek Fire and Gunpowder argued for crude petroleum thickened with resins to produce a sticky, slow-burning flame, possibly with sulphur or quicklime added to encourage combustion on contact with water [3]. The behavior described in the sources, particularly the surface-burning effect on the sea, fits the density profile of unrefined petroleum fractions reasonably well.
The Distilled-Naphtha Reading
A second reading, associated with the chemist and historian Adrienne Mayor and elaborated in part by the 1977 collected studies of Haldon and Byrne in Studies on the History of Constantinople, treats Greek fire as a more refined product: a light, distilled naphtha fraction produced in a closed apparatus and stored under pressure. This explains the projector design (which appears built for a low-viscosity, ignitable liquid) and the heating cauldron (which would vaporize the lighter fractions to assist ignition at the nozzle). It is harder to reconcile with the surface-burning descriptions, since pure naphtha tends to spread and burn off rapidly rather than clinging.
The Saltpeter Question
A persistent minority view, dismissed by most contemporary specialists, proposes that Greek fire contained an early form of saltpeter (potassium nitrate) or some other oxidizer that allowed combustion independent of ambient oxygen. The argument hinges on reports of underwater combustion. Alex Roland’s 1992 article “Secrecy, Technology, and War: Greek Fire and the Defense of Byzantium” rebuts this: documented saltpeter use in the eastern Mediterranean is much later, and surface burning on water does not require an oxidizer — a hot, sticky, low-density liquid will float and burn until it cools or disperses [4].
How a Working Weapon Was Forgotten
The disappearance of Greek fire is, methodologically, the most interesting part of the story. A working military technology, deployed continuously from the late seventh century into the twelfth, simply ceased to be replicable after the Fourth Crusade sacked Constantinople in 1204. The disappearance can be read in two competing ways, and the evidence does not yet decide between them.
Intentional Loss
The first reading takes Constantine VII at face value. Knowledge of the recipe was confined to a small hereditary corps of siphonatores, technicians attached to the imperial household. When the Crusader sack disrupted the Byzantine state in 1204, that compartmented knowledge was killed, scattered, or sold to no one in particular. Compartmentalization meant the technology could not be reconstructed even by the restored Palaiologan court after 1261. This is the version Alex Roland develops most fully: secrecy worked, and worked too well.
Gradual Decay
The second reading, advanced in part by the Dumbarton Oaks tradition of Byzantine military historians, argues that the formula was not a single secret but a complex of supply chains, fabrication routines, and tacit operator skill. As the empire lost control of the petroleum sources around the Black Sea and Caspian to Seljuk and Mongol expansion through the eleventh and twelfth centuries, the supply of the right feedstock dried up. Without the input materials, even an intact recipe could not have been executed, and the trained corps eventually had nothing to train on. The Smithsonian’s coverage calls this a “logistics extinction” — a framing echoed in the Byzantine tradition at Dumbarton Oaks.
The Open Questions
Greek fire remains genuinely unsolved, in a way that matters for how we read pre-modern technology generally. Three questions are still open and worth naming.
- Composition: No surviving residue has been chemically analyzed and confirmed as Greek fire. The Pergamon grenades and other recovered ceramics give suggestive but inconclusive data. A confident answer would require a sealed source still containing the substance, which has not yet been found.
- Continuity: Whether the weapon used at the 717-718 siege was the same substance as the one Anna Komnene describes her father deploying at Dyrrhachium in 1108 is not certain. The vocabulary stayed stable; the formulation may have drifted.
- Loss: The intentional-versus-gradual question above will probably only be settled by archive work in unedited Byzantine military manuscripts. Several promising codices in the Vatican and at Mount Athos remain only partly catalogued.
Why Greek Fire Still Matters
The weapon is more than a curiosity. It anchors a serious case study in how military secrecy interacts with technological survival, and it disciplines the historian against assuming that pre-modern people did not know what they were doing chemically. The Byzantines almost certainly did. They simply did not write the answer down for us.
For the History of Science
Greek fire pushes back against the older narrative that practical chemistry began in early modern Europe. The siphon apparatus and the apparent control of distillation fractions imply a working knowledge of pyrotechnics that historians of science have only recently begun to integrate into the longer story.
For Military History
The weapon shaped the eastern Mediterranean for half a millennium. Without Greek fire, the Arab assaults of the seventh and eighth centuries might have taken Constantinople, and the political map of the Near East would look very different.
Frequently Asked Questions
Who invented Greek fire?
The Byzantine chronicler Theophanes the Confessor credits a craftsman named Kallinikos, said to have come to Constantinople from Heliopolis in Roman Syria around 670. Kallinikos brought, or claimed to have developed, a projectable incendiary that the Byzantine state then weaponized at sea. Some scholars treat him as a real individual, others as a literary personification of a transferred body of pre-existing knowledge.
When was Greek fire first used in battle?
It appears decisively in the Byzantine sources during the first Arab siege of Constantinople, dated by Theophanes to 674-678, and was used to devastating effect during the second siege in 717-718. Some scholars compress the earlier engagements, but the second-siege use is well attested across Byzantine and Arabic sources.
What was Greek fire actually made of?
No surviving recipe exists. The two leading reconstructions propose either a thickened crude petroleum (Partington, 1960) or a distilled naphtha fraction (Mayor and others). A minority view adds saltpeter as an oxidizer; most specialists, including Alex Roland in 1992, find the saltpeter case unconvincing on chronological grounds.
Could Greek fire really burn on water?
Multiple Byzantine and Arab sources describe a flame that floated and continued to burn on the sea surface. A petroleum-based, thickened mixture would float on water by density and burn until it cooled or dispersed; this does not require an oxidizer. The exact behavior described, however, has not been precisely reproduced in modern conditions.
How was Greek fire delivered?
The principal delivery system was a bronze siphon mounted on a Byzantine dromon, fed from a heated reservoir and pumped under pressure. Hand-projected variants (the cheirosiphon, attributed to Leo VI) and ceramic grenades broadened the weapon’s tactical use over the ninth and tenth centuries.
Why did the recipe disappear?
Two theories compete. The intentional-loss reading argues that strict imperial compartmentalization, formalized by Constantine VII Porphyrogenitus, killed the technology when the Fourth Crusade disrupted Constantinople in 1204. The logistics-extinction reading argues that loss of access to specific petroleum feedstocks around the Black Sea and Caspian rendered the formula inexecutable even where it survived.
Is there any archaeological evidence of Greek fire?
Indirect, mostly. Excavations have recovered small thick-walled ceramic grenades plausibly associated with the weapon, particularly at Pergamon and other Byzantine military sites. Residue analyses have been inconclusive. No sealed sample of the original liquid has been recovered and chemically confirmed.
What sources should a serious reader start with?
James Riddick Partington’s A History of Greek Fire and Gunpowder (1960) remains foundational. Alex Roland’s 1992 article in Technology and Culture is the cleanest analytical statement on secrecy and loss. John Haldon and Maurice Byrne’s 1977 Studies on the History of Constantinople and John Pryor’s later work on Byzantine naval architecture together provide the best technical reconstruction of the delivery system.
