Nine centuries after the bloody crusades, Christians fought Muslims in the Bosnian War of the 1990s. But it wasn’t for religion that they fought. It was for control of Yugoslavia, broken up after the fall of communist control. When a new country was formed, the Bosnian territory, inhabited predominately by Christians, claimed its independence as a country and attacked the majority Muslim population. Again, a war over land, caused by changing borders. It was the worst European uprising since WWII.
And who can forget the Catholic and Protestant conflict that plagued Northern Ireland? When Ireland gained independence in 1922, Northern Ireland was exempt and its control remained with Great Britain. (While Southern Ireland is predominantly Catholic, Northern Ireland is Protestant. To protect the Protestant residents of Northern Ireland, Great Britain kept control.) Soon, the remaining Catholic minority in Northern Ireland was oppressed and fought back. Again, although it may have appeared so, this was not a religious conflict; rather, it was for control of land.
And now, with the development of ISIS, like the Christians in Ireland, Muslims are fighting among themselves—Sunni against Shia. But, it is not for religion that they fight, rather for control of land.