The Most Secret Weapon: Greek Fire

^{Siege engine throwing a barrel of flaming liquid into a frotress. The substance is often called Greek fire, but the original Greek fire was squirted through a nozzle on a ship.}

A huge Arab fleet was threatening Constantinople, the capital of the Eastern Roman Empire. A little more than a generation prior, Arabs were considered a rather minor nuisance – bandits who rode in from the desert to raid small settlements and who preyed on caravans that were not well‑guarded. But about 40 years before this, a crazy man in the Arabian town of Medina, who called himself a prophet, had gathered enough followers to unite all the Saracen tribes of Arabia. Then those wild Arabs swept over Palestine and Syria and in 636 destroyed a Roman army in the gorges of the Yarmuk valley. The next year, they decisively defeated the mighty Persian Empire, which, with the eastern Roman Empire, was one of the two superpowers of the world west of China. By 640, the Persian Empire was extinct – entirely under the thumb of these Arab barbarians who called themselves Muslims.

While one Arab army was gobbling up Persia, others conquered Babylon, invaded Egypt and swept across North Africa as far as Carthage. The Roman forces were unable to even slow them down. The Arabs also conquered the seafaring cities of Syria. By recruiting the sailors of Syria, heirs of the ancient Phoenicians, these desert fighters created a formidable navy. In 653, they took the island of Cyprus and two years later defeated a Roman fleet commanded by the emperor Constans himself.

In 672, they sent a fleet into the Sea of Marmara, right up to the gates of Constantinople. The Arab fleet was enormous, and the Empire had not yet recovered from the long and exhausting war with Persia that had ended 44 years prior. That war was the reason the Muslims had conquered Persia so easily.

Would the Romans be the second empire to fall before the Arab fury? The Arabs were certain that God had delivered this citadel of infidels into their hands. Their ships formed a line and swept down on the Roman ships that had filed out of their protected harbor. The Syrian sailors strained at their oars while the Arab warriors fitted arrows to their bowstrings. They noticed that the leading Roman ships were highly decorated. On the prow of each were gilded images of lions, bears, and other animals.

The Arabs were drawing their bows when a stream of liquid gushed from the open mouths of the gold lions and dragons. The liquid covered the Arab ships and almost immediately burst into flame. The terrified Arabs and Syrians sloshed water on the flames, but the fire burned on. What was left of the invasion fleet turned and fled. Few of them made it to the Dardanelles and back to the Mediterranean.

The Sons of the Prophet did not give up easily. Again and again they sent fleets against the city on the Golden Horn. And again and again, their ships were burned to the waterline by the terrible weapon that came to be called Greek fire.

No weapon in history has caused more speculation than Greek fire. The formula for it was zealously guarded for centuries, because the eastern Romans considered it a gift from God to the people of the Empire – the eastern bastion of Christianity against Islam and paganism. The Empire alone had Greek fire, but after the introduction of gunpowder the miracle weapon had gradually fallen out of use and was forgotten.

There has been plenty of speculation about the composition of Greek fire, probably because there are widely varying descriptions of the weapon by ancient sources. Not everything that has been called Greek fire is the material that was used to destroy those Arab fleets. That, according to the generally accepted tradition, was the invention of Callinicus, a Syrian architect. In 660, Callinicus, seeing the apparently unstoppable Muslim blitzkrieg, brought his invention to Constantinople in the hopes that it could save Christianity. In describing the destruction of the Muslim fleet, the East Roman chronicler Theophanes wrote: “Then it was that Callinicus, the architect of Heliopolis in Syria, who had invented a marine fire, set light to the vessels of the Arabs and burned them utterly, together with their crews.”

Writing some four centuries after the battle, Anna Comnena, the brilliant teenaged daughter of the eastern Roman Emperor Alexius, said, “On the head of each ship he had fixed a lion or other land animal made of brass or iron with the mouth open and gilded over, so that the mere aspect was terrifying. And the fire which was to be directed against the enemy he made to pass through the mouths of the beasts so that it seemed as if the lions…were vomiting the fire.”

Anna’s Alexiad, a history of the career of her father, is one of our best sources for the weapons available to the east Romans and their enemies. Anna’s writings also show that the east Romans had a variety of incendiary weapons. In another place, she describes an incendiary blowgun: “Readily combustible rosin is collected from the pine and other evergreen trees and mixed with sulfur.

Then it is introduced into reed pipes and blown with a strong continuous breath and at the other end fire is applied to it and it bursts into flame and falls like a streak of lightning on the faces of the men opposite.”

In 900, Emperor Leo the Wise may or may not have been describing the weapon used in 672 when he spoke of “fire prepared in tubes whence it issues with a noise of thunder and a fiery smoke which burns the ship at which it is directed.”

Later, the Crusaders reported that the Muslims attacked them with “Greek fire,” which was shot at them by mechanical siege engines. Jean of Joinville wrote that the Greek fire was in a container “as large as a barrel and a tail of fire that issued from it was as large as a large lance.” When the container landed, it exploded in a ball of fire that covered everything and everybody nearby. This weapon, which seems to have been a container of naphtha that was ignited just before firing was like a giant Molotov cocktail. It was definitely not the Greek fire Callinicus invented. Neither was the rosin‑and‑sulfur blowgun Anna Comnena described.

Most authorities today believe that Callinicus’s flamethrower projected a mixture containing quicklime and some extremely inflammable liquid such as naphtha or turpentine. Quicklime becomes extremely hot when mixed with water. In Greek fire, it became hot enough to ignite the liquid with which it was packed. It was probably projected through the animal heads by some kind of pump. Being projected from a low‑freeboard galley in the open sea, it would probably ignite almost as soon as it left the nozzle, and certainly when it hit the wet sides of the enemy ship. Other authorities believe that the incendiary mixture was released into another metal pipe into which sea water was being pumped. As soon as it hit the air upon leaving the animal head, it would burst into flame. As the burning substance was a liquid and lighter than water, throwing water on the flames did nothing but spread the fire. That led to a belief among hostile sailors that fire once started by Greek fire could not be extinguished. So Greek fire became a powerful psychological as well as physical weapon.

Greek fire changed warfare in the eastern Mediterranean for centuries, and it also changed the history of the world. If Callinicus had not invented Greek fire, Islam might have swept over Europe as it did over the Near East, north Africa, and central Asia.