Greek Fire – Greek warships would carry giant cauldrons filled with a mysterious incendiary liquid. Once in range of an enemy ship the Greeks would heat and pressurize the liquid then use a siphon to “squirt” it out across the sea in the direction of the enemy to devastating effect. The components of this fearsome ancient weapon were a closely guarded secret. Even the soldiers who helped prepare the fire did not know the ingredients. In 814 the Bulgarians captured two Greek warships, containing some 36 siphons. A few still contained the mysterious liquid used to make Greek fire, but without knowing the proper components the Bulgarians were unable to make use of it.
Modern scientists have been unable to figure out the exact makeup of the fire. Three possible combinations include petroleum, potassium nitrate and sulfur, naphtha, quicklime and sulfur or phosphorus and saltpeter. But the following is known from old records: Greek fire burned on water and according to some accounts was even ignited by water; it could be extinguished only by a few substances, including sand, strong vinegar and old urine and it was accompanied by thunder and much smoke.
“Every time they hurl the fire at us, we go down on our elbows and knees, and beseech Our Lord to save us from this danger,” wrote one witness who saw the weapon in action and lived to tell the tale.