Every now and then an atheist will posit the suggestion that religion is the cause of most wars. Well actually this is not the case. In fact the Encyclopedia of War (reference below) suggests that religion can be blamed as the cause of 6% of all wars. If you then look at the fact that Islam has been involved in half that number you soon realise that all non Islamic religions can be accused of causing 3% of wars.
Even when religion is cited as the cause of war e.g. in Ireland between Catholics and Protestants you find that the real reason is often something else. In the case of Ireland the root cause of the war was that one section of the population had more rites than the other.
Phillips, Charles and Alan Axelrod. Encyclopedia of Wars. New York: Facts on File, 2005