Greek fire was an incendiary weapon used by the Byzantine Empire from the seventh to the fourteenth centuries. The recipe for Greek fire was a closely-guarded state secret and has been lost to history
"The Roman fleet burns the opposite fleet down" – An Eastern Roman / Byzantine warship using their "secret weapon" Greek fire against a ship belonging to the rebel Thomas the Slav, AD 821. (12th century illustration from the "Madrid Skylitzes").
Use of a cheirosiphōn ("hand-siphōn"), a portable flamethrower, used from a flying bridge against a castle. Illumination from the Poliorcetica of Hero of Byzantium.
Proposed reconstruction of the Greek fire mechanism by Haldon and Byrne
Napalm is an incendiary mixture of a gelling agent and a volatile petrochemical. The name is a portmanteau of two of the constituents of the original thickening and gelling agents: coprecipitated alum
Greek fire
…saltpeter, sulfur, or quicklime, but most modern scholars agree that it was based on petroleum mixed with resins, comparable in composition to modern napalm. Byzantine 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…
Results of a napalm strike by the United States Army Air Force on a Japanese outpost off the coast of the island of Borneo
A "Zippo" riverboat of the US Brown-water navy firing an ignited napalm mixture from a riverboat-mounted flamethrower in Vietnam
Phan Thi Kim Phuc, burned with napalm at the age of 9 during the Vietnam War (1972)