Greek fire was the most devastating weapon in the Eastern Roman empire. But what was it?

Before modern weapons of mass destruction, there was Greek fire (ignis graecus). This was the term medieval Crusaders applied ...
La Brújula Verde

Greek Fire, the Byzantine Empire’s Secret Incendiary Weapon That Survived Until the 19th Century

They began to blow with blacksmiths’ bellows into a furnace where there was fire, and from it came a great noise. There was also a brass [or bronze] tube, and from it came much fire against a ship, ...