The Secret Ancient Weapon That Changed History...

Greek Fire is one of history’s great mysteries. A weapon so powerful that it struck fear into the hearts of entire fleets and armies, yet so secret that even today, no one knows exactly how it was made. It was more than just a weapon; it was an instrument of survival, an edge that kept an empire alive…

Greek Fire first appeared in the late 7th century during the reign of Byzantine Emperor Constantine IV (668–685). The invention is credited to a Syrian engineer named Kallinikos (or Callinicus), who fled from the advancing Muslim armies and sought refuge in Constantinople. He supposedly brought with him knowledge of an incendiary weapon unlike anything the world had seen before.

It wasn’t just any fire. Greek Fire burned on water. In naval warfare, this was a nightmare for enemies. Once ignited, it stuck to ships, armor, and flesh, continuing to burn despite attempts to douse it with water. The Byzantines didn’t just have fire; they had fire that could not be put out.

The Byzantine navy deployed Greek Fire primarily through siphons mounted on their warships. These were essentially primitive flamethrowers, capable of spewing the liquid fire directly onto enemy vessels. There are also records of it being used in clay pots or grenades thrown onto enemy ships or fortifications.

Its first major recorded use was in 672 during the Arab siege of Constantinople. The Umayyad Caliphate had been expanding rapidly, and Constantinople was their ultimate prize. The Byzantine defenders, vastly outnumbered, turned to their secret weapon. As the Arab fleet approached, Byzantine ships unleashed jets of Greek Fire, setting their enemies ablaze. The siege failed, and Constantinople was saved.

Over the next few centuries, Greek Fire became a cornerstone of Byzantine naval dominance. It was used in numerous battles, including:

717–718: The Second Arab Siege of Constantinople.

The Umayyad fleet entered the Bosphorus in 717, confident that this time, Constantinople would fall. Their ships filled the strait, blocking supply lines and cutting off the city from aid. Victory seemed inevitable.

Then the Byzantine fireships moved in.

From a distance, they looked ordinary. But as they closed, Byzantine crews unleashed jets of liquid flame. It clung to wood, water, and flesh, burning with an intensity that nothing could extinguish. Umayyad sailors leapt overboard, only to find the fire floating on the waves. Their fleet turned to chaos—ships colliding, crews abandoning their posts, the water itself turning into a battlefield.

By spring, the siege collapsed. The Umayyads, weakened by starvation and Bulgar raids, withdrew. Constantinople endured. The empire survived. The fire had done its work.

941: The Rus' invasion under Igor of Kiev.

In 941, Igor of Kiev led a Rus’ fleet into the Bosphorus, expecting easy plunder. The Byzantines were distracted, their main forces away fighting in the East. The waters of the strait belonged to the invaders—until the fireships arrived.

The Rus’ had never seen anything like it. Byzantine dromons closed in, and suddenly, fire erupted from their bows. It wasn’t just flame—it stuck to ships, to shields, to men. The sea itself seemed to burn. Warriors jumped overboard, only to be swallowed by fire on the water. Their fleet turned to ruin in moments.

The survivors fled. Some were captured, others drifted back north to tell of the disaster. Igor tried again years later, but only after making peace first. The memory of the burning sea had done its work.

11th and 12th centuries:

Through the 11th and 12th centuries, Greek Fire still burned, but not as brightly. The Byzantines used it in their wars, but the empire was no longer what it had been. Enemies grew stronger, while the state grew weaker.

It was still there in naval battles—flames licking across the water, setting enemy ships ablaze. But by now, it was more legend than weapon. The Byzantines had fewer ships, fewer men trained to wield it, and fewer victories to celebrate.

When the Crusaders arrived, they saw it in action. When the Normans attacked, they felt its heat. But Greek Fire was no longer deciding wars. The enemies of Byzantium had learned to fear it—but they had also learned to endure it. The empire that had once ruled the seas was fading, and with it, the fire that had once made it untouchable.

The precise composition of Greek Fire remains unknown. The Byzantines guarded its secrets fiercely. Only a select few knew how to make it, and the knowledge was passed down through generations within a tightly controlled bureaucracy. Some say the formula was lost when the empire fell into decline, others believe it was never written down in the first place.

Speculation about its ingredients has ranged from petroleum-based compounds to quicklime, sulfur, naphtha, and resin. The key factor was its ability to ignite upon contact with water or to sustain flames despite water dousing. This has led modern scientists to theorize that it may have involved a form of crude oil or a chemical reaction triggered by water.

When the Byzantine Empire finally fell in 1453 to the Ottomans, Greek Fire had already been lost. Whatever formula had once existed, it died with the empire’s decline. Some say the knowledge was deliberately destroyed to keep it from falling into enemy hands. Others think it was simply forgotten in an age of chaos and decline…

The greatest weapons in history are often not those that conquer but those that defend. Greek Fire wasn’t used to build an empire, but to preserve one. And for centuries, it did just that.