Kallinikos, an architect and engineer originally from Heliopolis (Syria), arrives in Constantinople as a refugee following the Muslim conquest of his region, during the reign of Constantine IV (668-685). Around the year 672 he develops a liquid incendiary mixture — probably composed of petroleum or naphtha together with resins and other ingredients never revealed — that burns on the surface of water and resists conventional extinguishing methods. Launched via bronze siphons mounted on dromons (Byzantine warships), it proves decisive in repelling the first Arab fleet besieging Constantinople. The chronicler Theophanes the Confessor recounts that "Kallinikos, an artisan from Heliopolis, fled to the Romans. He had devised a sea fire that burned the Arab ships and consumed them with their crews." The exact formula remained a jealously guarded state secret for centuries and is definitively lost with the empire's fall. Decades later, Emperor Leo VI the Wise documents in his Tactica a portable version of the same technology, the cheirosiphon (hand-siphon), used by infantry in sieges.