Byzantine Weapon Called Greek Fire

For centuries, an incendiary weapon of the Byzantine Empire was a crucial part of the defense of Constantinople. 

In Byzantine texts, the weapon was known as “Υγρό Πυρ” (Ygro Pyr) or “Liquid Fire”.

Greek Fire was used by the Byzantines, in naval warfare, with the first recorded use in 678 AD, during the Arab-Byzantine Wars.

Arab forces, attacking Constantinople, were repelled with a flame that water could not extinguish.

A Syrian born in Heliopolis (modern day Baalbek, Lebanon), named Kallinikos, is credited with the invention of Greek Fire.

It is believed that Kallinikos fled to the Byzantine capital, from Syria, escaping the Arab conquest and bringing with him the formidable weapon. 
Modern reconstruction of the Cheirosiphon, or hand-held Greek Fire, Athens, Greece
The precise composition of Greek Fire remains unknown but research suggests that possible ingredients are pine resin, naphtha, quicklime, calcium phosphide and sulphur.

Byzantine grenades, which appeared around the reign of Leo III (717-741 AD), were also used by the Byzantine military, and filled with Greek Fire.

These ceramic explosive jars were probably thrown by hand, in short-range battles. Or, flung at the enemy with catapults, lighted before release or after, with arrows.
Byzantine grenades, which appeared around the reign of Leo III (717-741 AD)
Greek Fire was an important part of Constantinople’s struggle against Arab sieges.