 During the Peloponnesian War, Boeotians used some kind of a flamethrower trying to destroy the fortification walls of the Athenians during the Battle of Delium.Later, during the Byzantine era, sailors used rudimentary hand-pumped flamethrowers on board their naval ships.Greek fire, extensively used by the Byzantine Empire, is said to have been invented by Kallinikos of Heliopolis, probably about 673.