The supremacy of the Byzantine navy was undoubtedly due to the existence of an amazing weapon: Greek fire, also known as “sea fire”, “Median fire” or “manufactured fire”. People had known how to launch combustible liquids since ancient times, in the form of flaming arrows or flammable materials in containers. Greek fire appears to have been the most powerful of all because it did not extinguish on coming into contact with water.

According to the historian Theophanes, Greek fire was invented by the Greek-Syrian architect Callinicos ; the Byzantines used it for the first time against the Arab navy during the siege of Constantinople in 717-718. Given that the constituents involved in making Greek fire were known in antiquity, Kallinikos’ contribution could have been in the way it was propelled.

The composition of Greek fire remains a mystery even to this day, since both the ingredients and the preparation method were a state secret. Constantine Porphyrogenitus even threatened to excommunicate anyone betraying the secret formula, which was said to have been revealed to Constantine the Great by an angel sent from God. It is believed that Greek fire was a mixture of sulphur and naphtha , a flammable mineral oil like crude oil found in the area between the Caspian Sea and the Black Sea, as well as in Arabia. It would, however, also have contained other combustible substances to aid ignition, such as quicklime and resin.

Apart from the Byzantines, it seems that the Arabs knew and used incendiary mixtures both on land and at sea, consisting mainly of naphtha and liquid tar, which could only be put out with sand, not water. This is hardly surprising considering that the two peoples were in constant contact with each other, especially in the first millennium. They would certainly have spied on each other, and the numerous prisoners on both sides would have passed on information to the opposite camp, especially when the enemy had already managed to get his hands on the secret weapon.

Greek fire was kept in oblong clay or metal vessels called siphons. These were doused in the same mixture and set alight immediately before being launched, or wrapped in fabric soaked in the mixture, which was likewise set on fire. In some cases the siphons had fire torches that must have worked just like modern day bomb fuses. The siphons were launched from special throwing machines located in the prows of ships. These machines were probably ballistae, i.e. large wooden structures that had a mechanism similar to a bow that fired stones or arrows. The ballistae were of various sizes, depending on the type or size of the ship using them, covered on the outside with the heads of wild beasts made in metal that had fire and smoke coming out of their mouths. There were also “cheirosifones” (hand siphons), which were probably small clay or metal pots filled with Greek fire, which would be thrown at the enemy like modern grenades.

The main success of liquid fire was that it created confusion and panic among enemy ships, which immediately burst into flames - fire is the worst possible thing that could happen to a wooden ship on the open sea during a naval battle. Greek fire was employed by the Byzantines up to the 13th century. The last time we hear of its use is at the Fall of Constantinople: Frantzis the historian relates that Greek fire drove back the Ottomans who were digging tunnels under the city walls, while it was also used by Francesco Lecanella (Phlatanellas), governor of a ship chartered by Constantine XI Palaeologus, who defeated a flotilla in the Ottoman fleet during a naval battle in the Bosphorus on 20^th April 1453.