Go back as far as you want, I stand by my statement. Sammy nailed it, economics, not religion were responsible for most wars. Religion has been responsible for its fair share of wars but not most, at least not most of those documented in history.
The Spanish conquered the New World while holding the mighty cross at the front of their armies, but they were really here to plunder the gold and whatever wealth they could ship back to Spain. The Roman Empire, the Mongolians, Egypt, Napoleon/France, The British, Germany, Japan, it was all about expansionism, conquest, and increasing their territory, raw materials and net worth.