I majored in History at school and I remember my teacher saying no war was over religion. The classroom challenged him and in every case we came up with he showed that politics or profit were the true motives. Cloaking the real motives with religion makes war more acceptable to people and more willing to fight. You may be willing to die for God and a heavenly reward but would you die to make somebody richer? There is a great scene in movie Braveheart when the Scotish soldiers see the size of the English army doubt sets in:

Young soldier: I didn't come here to fight so they can own more lands; then I have to work for them.
Veteran soldier: Nor me. Alright lads. I'm not dying for these bastards! Lets go home.

But when Wallace appealed to a higher motive, nationalism, they stayed and fought. Religion, like nationalism is just a motivator for the masses. Incidentally for those soldiers it didn't really matter who won, English or Scots, they would still be "working" just a different nobleman owning the land.