<P> The Muslim navies eventually adapted themselves to it by staying out of its effective range and devising methods of protection such as felt or hides soaked in vinegar . </P> <P> In C.J. Sansom's historical mystery novel Dark Fire, Thomas Cromwell sends the lawyer Matthew Shardlake to recover the secret of Greek fire, following its discovery in the library of a dissolved London monastery . </P> <P> In Michael Crichton's sci - fi novel Timeline, Professor Edward Johnston is stuck in the past in 14th century Europe, and claims to have knowledge of Greek fire . </P> <P> In Mika Waltari's novel The Dark Angel, some old men who are the last ones who know the secret of Greek fire are mentioned as present in the last Christian services held in Hagia Sophia before the Fall of Constantinople . The narrator is told that in the event of the city's fall, they will be killed so as to keep the secret from the Turks . </P>

When was greek fire last used in warfare