Interesting new book regarding the Crimean War where European Christians and the Islamic world joined forces against Russia, Turkey, and the Eastern Orthodox.:

Yet for all its modernity, the fighting was also a "holy war" for each belligerent power. Leaders used religious rhetoric and ordinary soldiers and sailors said their prayers as they tried to make sense of what they were doing. That, presumably, is the point Orlando Figes, a historian at Birkbeck College in London, is making with his British subtitle, "The Last Crusade". His book reveals the strange mixture of meanings the war had for its combatants. He puts the conflict into its broader context: the determination of Britain (and with some reservations, France) to stem Russian expansion and to bolster Islam in its fight with eastern Christianity.

No, that last point is not a mistake.