They started the war with the rest of the world.
If the Religion of Peace gets any more peaceful there will be no infidels allowed to live on the planet.
The Crusades ended with a sort of wimpy Iran Memo of Understanding in a way. Still going on with only the Islamists fighting.
History News:
The Crusades in the Middle East effectively ended in 1291 when Muslim Mamluk forces successfully captured Acre, the last major Christian stronghold in the Holy Land. This defeat triggered a domino effect, leading to the rapid fall of remaining Crusader towns like Beirut, Haifa, and Tyre.
...After repeated failures, massive costs, and shifting political priorities back home, enthusiasm for crusading in the Holy Land drastically faded.