Two world wars within a generation and the potentialities of nuclear warfare have made the establishment of international order and the preservation of International peace the paramount concern of western civilization. War has always been abhorred as a scourge. As the rise of the territorial state transformed the Holy Roman Empire from the actual political organization of Christendom into an empty shell and a legal fiction writers and statesmen reflected more and more on substitutes for the lost political unity of the western world. Erasmus in the sixteenth century, Sully, Emeric Cruce Hugo Grotius, and William Penn in the seventeenth, and the abbe desaint-pierre, Rousseau Bentham and kant in the eighteenth were the great intellectual fore-runners of the practical attempts undertaken in the nineteenth and twentieth centuries to solve the problems of international order and peace.

Of these attempts, the Holy Alliance the, Hague peace conferences of 1899 and 1907, the League of the Nations and the United Nations are the outstanding examples. These organizations and conferences, together with other less spectacular endeavors to shape a peaceful world, were made possible by four factors-spiritual moral, intellectual and political which started to converge at the beginning of the nineteenth century and culminated in the theory and practice of international affairs prevalent in the period between the two world wars.

Science the times of the stoics and the early Christians, there have been alive in western civilization a feeling for the moral unity of mankind which strives to find a political organization commensurate with it. The Roman Empire was such a political organization of universal scope. After its downfall, the Roman Empire remained throughout the ages a symbolic reminder of the unity of the western world and the ultimate goal and standard which inspired Charlemagne no less than Napoleon and determined the policies of the Holy Roman Empire until the beginning of the religious wars. It is not by accident that the dissolution of the Holly Roman Empire in 1806 coincided with Napoleon's attempt to revive it and antedates by little less than a decade the beginning of that period of modern history which has made the restoration of international order one of its major objectives.