"It needs but one foe to breed a war, and those who have not swords can still die upon them"
The Rock is the earliest projectile weapon. Readily available, easy to use, and it can be delivered with lethal force well outside of the reach of your foe. Of course there were many weapons available before the rock...teeth, claws, hands, and eventually tools, such as the club became aids to killing. The rock removed the up close and personal weapons, by providing distance to the act. We have been increasing our distance from each other ever since.
Inventions such as the bow, the rifle, and even nuclear tipped rockets are just instruments in the human toolkit of war. The most deadly of our weapons are not the ones we manufacture....it is the one we all possess...our brain. We have taken the savage approach to killing and elevated it to a fine tuned art.
War is subtle like a flower that slowly perfumes its world. Not overpowering in its approach, war just slowly enters into your brain until it becomes a scent that can not be resisted. It is as natural as breathing and by the time you discover it is the dragon of pain and death...it is too late.