Greek Fire: The Military Secret That Saved The Byzantine Empire

Published January 10, 2015
Updated March 25, 2020
Published January 10, 2015
Updated March 25, 2020

This sophisticated ancient weapon played a key role in the remarkable survival of the Byzantine Empire against countless enemies, helping them burn enemy ships and break sieges.

Depiction Of Greek Fire Used At Sea

Wikimedia CommonsOne of the few surviving depictions of Greek fire being used at sea against Thomas the Slav, a 9th-century rebel Byzantine general.

Greek fire was a devastating incendiary weapon used by the Byzantine Empire to defend against their enemies.

The Byzantines successfully used it to repel Arab invasion for hundreds of years, particularly at sea. While it wasn’t the first incendiary weapon, it was arguably the most historically significant one.

What’s truly fascinating about Greek fire is that armies that captured the liquid along with the machine that delivered it were unable to replicate either of them. To this day, nobody knows exactly what ingredients went into the mixture.

A Powerful Ancient Weapon

Byzantine Empire In 600 AD

Wikimedia CommonsThe Byzantine Empire in 600 AD. It would suffer continued attacks from Arabs throughout the centuries, culminating in the 1453 fall of Constantinople.

Greek fire was an incendiary liquid weapon devised by the Byzantine Empire, the surviving, Greek-speaking Eastern half of the Roman Empire with its capital in Constantinople.

Also called “sea fire” and “liquid fire” by the Byzantines themselves, it was heated, pressurized, and then delivered via a tube called a siph┼Źn. Greek fire was used mainly to light enemy ships on fire from a safe distance.

What made Greek fire so unique and potent was its ability to continue burning in water, which prevented enemy combatants from dousing the flames during naval engagements. It’s even possible that it ignited upon contact with water.

To make matters worse, Greek fire was a liquid concoction that stuck to whatever it touched, be it the hull of a ship or human flesh. Indeed, Greek fire was only extinguishable with three things: sand, vinegar, and — bizarrely — old urine.

The Invention Of Greek Fire

Greek Fire

Wikimedia CommonsThe handsiphon, a hand-held Greek fire flamethrower depicted in a Byzantine military manual as a way to attack a besieged city.

Greek fire was invented in the 7th century by one Kallinikos of Heliopolis, a Jewish architect who fled from Syria to Constantinople after an Arab attack on his home city.

In fact, Kallinikos invented not only the liquid itself but also the complex contraption that projected Greek fire onto enemy ships, which included a long tube and presumably a furnace-like design to produce the pressure and heat required.

These complex devices were then attached to the prows of specially designed Byzantine fire ships. When used, the pressurized liquid would shoot out, igniting jets of fire that shot out across the water.

Greek fire was not only incredibly effective but also intimidating: it reportedly produced a loud roaring noise and large amounts of smoke, much akin to the breath of a dragon.

Because of its devastating power, the formula for creating Greek fire was a tightly guarded state secret. It was known only to Byzantine emperors and the Kallinikos family and handed down from generation to generation.

This practice was clearly effective: even when the enemy managed to get their hands on Greek fire, they had no idea how to reverse engineer the technology for themselves. However, this is also the reason why the secret of making Greek fire was lost along with the Byzantine Empire.

Greek Fire: The Byzantine Savior

Walls Of Constantinople

Wikimedia CommonsGreek fire played a big role in ensuring the survival of the Byzantine capital of Constantinople against repeated Arab sieges.

The immediate reason for Kallinikos’ invention of Greek fire was simple: prevent his new homeland from falling to the Arabs. To that end, it was first used to defend Constantinople against Arab naval incursions.

Greek fire was so effective at repelling the enemy fleet that it played a major role in ending the First Arab Siege of Constantinople in 678 AD.

It was similarly successful during the Second Arab Siege of Constantinople from 717-718 AD, again dealing massive damage to the Arab navy and allowing the city to be resupplied by sea.

Greek fire continued to be used by the Byzantines for hundreds of years not only in conflicts against outsiders but also during civil wars. In this sense, it played a significant role in the continued survival of the Byzantine Empire against countless enemies.

Some historians even argue that by keeping the Byzantine Empire defended for centuries, Greek fire was instrumental in saving the whole of Western civilization from a Muslim Arab invasion.

Greek Fire Flamethrower

Greek Fire Flamethrower

Wikimedia CommonsClose-up of the hand-held version of the Greek fire device from a Byzantine siege manual.

Although Greek fire remains best known for its use at sea, the Byzantines used it in many other creative ways. Most famously, Byzantine Emperor Leo VI the Wise’s 10th-century military treatise Tactica mentions a hand-held version: the “cheirosiph┼Źn,” an ancient version of a flamethrower.

This weapon was reportedly used in sieges both defensively and offensively: to burn siege towers as well as enemy defenders. Some contemporary authors also recommended using it on land to disrupt enemy armies.

In addition, the Byzantines filled jars with Greek fire that could function similar to grenades and doused caltrops in the liquid before firing them out into the enemy to slow their advance.

Greek Fire Grenades And Caltrops

Wikimedia CommonsJars of Greek fire and caltrops that were presumably doused in the liquid. Retrieved from the Byzantine fortress of Chania.

Recreating The Formula

The Greek fire formula was imitated by other people over the centuries. For example, there are even historical records of the Arabs themselves using their version of Greek fire against crusaders during the Seventh Crusade in the 13th century.

Interestingly, the whole reason it’s called Greek fire is that’s what the crusaders called the Byzantines.

To other people who experienced its terrible power — such as the Arabs, Bulgars, and Russians — the more common name was actually “Roman fire,” since the Byzantines were a continuation of the Roman Empire.

Greek Fire Catapult

Wikimedia CommonsDepiction of a 13th-century catapult supposedly used to throw Greek fire.

But none of these imitations could measure up to the real thing. To this day, nobody knows exactly what went into making this powerful weapon.

Although petroleum, quicklime, sulfur, niter, and some sort of resin have been proposed as the ingredients used in Greek fire, nobody knows the true formula.

The mystery of Greek fire continues to captivate historians and scientists attempting to figure out its contents. It’s such a fascinating mystery that George R.R. Martin quite likely used it as the inspiration for the wildfire used in the Game of Thrones books and TV show.

But regardless of how it was made thing’s for sure: Greek fire was one of the most influential military inventions in human history.

National Geographic recreation of Greek fire.

Next, learn of the defining battles of Ancient Greece. Then, read about Commodus, the mad Roman Emperor forever immortalized in the movie Gladiator.

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