Man taxes his ingenuity to be able to kill without running the risk of being killed, Colonel Ardant Du Picq reminds us:
When people become more numerous, and when the surprise of an entire population occupying a vast space is no longer possible, when a sort of public conscience has been cultivated within society, one is warned beforehand. War is formally declared. Surprise is no longer the whole of war, but it remains one of the means in war, the best means, even to-day. Man can no longer kill his enemy without defense. He has forewarned him. He must expect to find him standing and in numbers. He must fight; but he wishes to conquer with as little risk as possible. He employs the iron shod mace against the staff, arrows against the mace, the shield against arrows, the shield and cuirass against the shield alone, the long lance against the short lance, the tempered sword against the iron sword, the armed chariot against man on foot, and so on.