Greek fire was an incendiary chemical weapon manufactured in and used by the Eastern Roman Empire from the seventh through the fourteenth centuries. The recipe for Greek fire was a closely-guarded state secret, but historians speculate it may have been made by combining pine resin, naphtha, quicklime, calcium phosphide, sulfur, or niter. Roman sailors would toss grenades loaded with Greek fire onto enemy ships or spray it from tubes. Its ability to burn on water made it an effective and destructive naval incendiary weapon, and rival powers tried unsuccessfully to copy the material.

Incendiary weapons, incendiary devices, incendiary munitions, or incendiary bombs are weapons designed to start fires or destroy sensitive equipment using fire, using materials such as napalm, thermite, magnesium powder, chlorine trifluoride, or white phosphorus. Though colloquially often known as bombs, they are not explosives but in fact are designed to slow the process of chemical reactions and use ignition rather than detonation to start or maintain the reaction. Napalm, for example, is petroleum especially thickened with certain chemicals into a 'gel' to slow, but not stop, combustion, releasing energy over a longer time than an explosive device. In the case of napalm, the gel adheres to surfaces and resists suppression.