It may be remarked, by way of preface, that the old idea of war regarded hostilities as working the absolute interruption of all relations between belligerents, save those arising from force; it also regarded the enemy as a proper object of violence and depredation. Even in the time of Grotius the universal usage permitted the putting to death of all persons found in the enemy’s territory, and in the terrible struggles of the Thirty Years’ War in Germany and the Eighty Years’ War in the Netherlands the story of the fate of men, women, and children at the hands of a conquering soldiery forms one of the darkest chapters in human history. But while Grotius declared this to be the usage, he also took care to point out that considerations of justice and mercy dictate a better course, and he made a distinction between certain classes, declaring that justice requires the belligerent to spare those who have done no wrong to him, especially old men, priests, husbandmen, merchants, prisoners, women, and children. This merciful distinction was eagerly seized upon by his successors, who gradually developed out of it different rules for the treatment of the “combatant” and “non-combatant” portion of the enemy inhabitants. After the Peace of Westphalia in 1648, which marked the close of the great struggles that had so long convulsed Europe, the older and more brutal customs fell into disuse, and the theory that only so much stress should be put upon an enemy, and primarily upon the combatant portion, as was sufficient to destroy his power of resistance was substituted for it. Along with this new usage grew the ever-increasing rights of neutrals, among them being that of trade and commerce with the non-combatant portion of belligerent states, which has done so much to lighten the hardships of war suffered by those devoted to peaceful pursuits in the enemy’s territory. The next important step in this evolution belongs to the present century, and is due to the enlightened initiative of the United States. This step consisted in the preparation of a manual containing a code of rules for the conduct of land warfare. Keenly alive to the inevitable sufferings incident to the great civil conflict then being waged, Abraham Lincoln commissioned Francis Lieber to prepare a series of rules for the conduct of the armies of the republic in the field which should set bounds to the passions of the soldiery.[I] In pursuance of this commission, a code of rules was prepared and adopted which has since been known as Lieber’s Manual; it was published in 1863, and proved a blessing to soldier and civilian alike. So obvious, indeed, were its good results that other nations rapidly followed the lead of the United States, and similar manuals were issued by Great Britain, France, Germany, Russia, and other powers. [I] See Pierantoni, Die Fortschritte des Völkerrechts im neunzehnten Jahrhundert.