In The Serpentine Key, the secret to Greek Fire is stolen through the subterfuge of a member of the imperial family itself and used as a bargaining chip in the intrigues surrounding the rebellion against Basil II in the 980s.
Greek Fire was an incendiary weapon, most famously used by the Byzantine Empire from at least the seventh century C.E., eventually being lost to obscurity, some say by the end of the thirteenth century. Greek Fire is most famous for being able to burn on water and reputedly not being able to be extinguished with water. Some even said that water fueled its flames. The only things that could extinguish it were supposedly vinegar and stale urine, both of which were used to infuse cow hides which were then placed over fortress walls and ships to protect them from igniting. This was useful knowledge for those against whom Greek fire was used, including the Rus, Bulgarians, Turks and others. In 814, the Bulgarians captured several barrels of the stuff and 36 siphons, but because of the complex nature of operating the devices, they went unused. In 941, the liquid was used against the Rus with deadly efficacy. Liudprand of Cremona remembered this event when he wrote: “The Rus, seeing the flames, jumped overboard, preferring water to fire. Some sank, weighed down by the weight of their breastplates and helmets; others caught fire.” Those who escaped were captured and executed. The Rus never again attempted to besiege Constantinople, preferring in later years to guard the city in the capacity of the Varangian Guard.
It is telling that this weapon was not called Greek Fire in its own time. Indeed, the Byzantines who thought of themselves as nothing by Roman, would have been insulted by the appellation of Greek, even though it was the language most in the Empire spoke. Instead it was called Roman fire, Kallinikos fire, sea fire, liquid fire and even wild fire, and it is this latter name that George R.R. Martin in his Song of Ice and Fire series chose for the green fire used by the characters in his fantasy.
Greek fire is credited to a Syrian known as Kallinikos or Callinicus. Supposedly, his descendants, a family by the name of Lampros, were responsible for guarding the secret. This story in itself is controversial. The name Lampros means “Brilliant” Was this a cover for the people who were in charge of keeping it secret? It has been said the the secret was never written down, but was given into the care of three alchemists who each knew a portion of the formula, but not all of it, so that it could not be stolen. Were these alchemists of the Lampros family? Or were they members of a family at all, but actually more of a secret organization charged with the security of the Byzantine Empire?
Incendiary weapons were hardly new to the scene when Kallinikos came along. They are depicted as being used by the Assyrians and are mentioned numerous times in historical records. So what made Greek Fire so special? There were a lot of people who wanted to get their hands on it and the Byzantines would do a lot to keep it out of the hands of their enemies. It was said that on his deathbed, Romanos II, charged his son (Basil II’s father) to never deliver the secret to the enemies of the empire, declaring the weapon to be a gift from the angels and “not to prepare this fire but for Christians, and only in the imperial city”. In addition to the alchemists who compounded the secret formula, there was also the task of constructing the siphons through which the liquid was propelled at other ships. Furthermore, the men who operated the siphons needed to be trained to effectively operate them. The siphons would likely have been a device in which the liquid was heated in a sort of covered cauldron, whereupon it would have been forced through a siphon that was pumped, giving it the necessary pressure to effectively spray the heated liquid over a good distance with deadly effect. Those operating this system would likely have needed some sort of protective covering, perhaps leather garments soaked in vinegar or stale urine.