Greek fire
Greek fire was an incendiary weapon used by the Byzantine Empire. The Byzantines typically used it in naval battles to great effect as it could continue burning even on water. It provided a technological advantage, and was responsible for many key Byzantine military victories, most notably the salvation of Constantinople from two Arab sieges, thus securing the Empire's survival. Greek fire proper however was invented in c. 672, and is ascribed by the chronicler Theophanes to Kallinikos, an architect from Heliopolis in the former province of Phoenice, by then overrun by the Muslim conquests. It has been argued that no single person invented the Greek fire, but that it was rather “invented by the chemists in Constantinople who had inherited the discoveries of the Alexandrian chemical school...”.