During the century following the Peloponnesian War, however, there seems to have been a positive advance in this domain. In this period the grosser atrocities of war were in a measure mitigated by a growing humanitarian sentiment. But all efforts to humanize war seem to have been limited to wars between Greek and Greek. From first to last in Greek history war against barbarians was waged practically without the least mitigation of its primitive barbarities. It was the practice of Alexander the Great in his campaigns in Asia to massacre the men of non-Greek cities taken by assault, and to sell the women and children as slaves. We hear no protest, even on the part of the philosophers, against these atrocities so long as it is non-Greeks who are the victims of them. But though the efforts of the Greeks to regulate and limit the rights of the conqueror were confined to wars of Greek against Greek, still these efforts are significant as a sign of an awakening ethical sentiment in this domain. This is a prophecy of a future day, distant though it be, when the growing conscience of mankind shall have rendered wars between civilized nations an impossible crime. [Sidenote: Efforts to prevent war by arbitration] The common Greek conscience never condemned war in itself. There never sprang up in Greece an agitation like the Peace Movement of to-day in Christendom. How deeply ingrained in the Greek mind was the conviction that war is a part of the established order of things is shown by the fact that their treaties ending open hostilities were ordinarily drawn for a limited term of years. They were merely truces, as though peace were only an incident in international relations.