1100s

Byzantine scholar who provided the earliest written description of Greek fire. This incendiary, developed for military purposes, had existed for several centuries and gave Byzantine forces a decisive advantage in numerous engagements. Marcus, also known as Marcus Gracchus, gave the formula for Greek fire thus: "Take pure sulfur, Tarter [salt produced by the reaction of tartaric acid with a base], Sarcocolla [Persian gum], pitch, dissolved nitre, petroleum [available in surface deposits throughout the Middle East and nearby areas] and pine resin; boil these together, then saturate tow [linty cloth] with the result and set fire to it."