The Shift from Ritual Combat to "Real" War.
►The development of classical civilizations, with their agricultural surpluses, increased populations, and improved technologies, advanced the business of making war.
►More people fought and suffered during hostilities.
►In most contemporary civilizations warfare was little organized and subject to ritual rules.
►Duels between warrior champions were important.
►Change came during the late Zhou period when Sunzi produced a great classic of military theory, The Art of War.