Greek fire: an incendiary weapon used by the Byzantine Empire noted for its extraordinary utility, being able to burn atop water and notoriously difficult to put out.
So what if the secret to the creation of Greek fire was never lost, either by a surviving Byzantine empire or the formula being recreated/adopted by another state, like, for example say the Venetians or the British?
How does this effect naval warfare? Especially during the age of exploration and gunpowder? What if its monopoly is lost and it becomes a common tool in the arsenal of navies everywhere?