[wozniacki]

  Sure. Previous to the 20th century, most wars were 
  fought  over control over resources, land, and 
  prestige.

Or over spurious differences like incompatible belief systems and divinities.

Spurious differences but holding a great deal of emotional charge.

edit: added quote.

[thaumasiotes]

From the 1974 The Four Musketeers:

    Porthos: I mean, what are we killing them for?
        Because they sing psalms in French, and we
        sing them in Latin?

    Aramis: Porthos, have you no education? What
        do you think religious wars are all about?