Greek Fire

The Romans invented yet another tactical weapon in the seventh century AD. This contentious weapon was thought to have been invented by Syrian engineer Callinicus, and it used a vicious "liquid fire" that could burn while floating on water.

It utilized a flammable substance emitted by the weapon and was used to set fire to hostile ships. Its most notable attribute was that it ignited when it came into touch with water, which greatly aided the Romans during maritime wars, particularly those undertaken by the Eastern Roman Empire.

However, the method of creating Greek fire remained a well-guarded military secret. A few writers from the time period explain how Greek fire could be effectively fought using sand and potent vinegar.