In the beginning of the seventeenth century, Grotius laid the foundations of a code of universal law (_De Jure Belli et Pacis_, 1625) independent of differences of religion, in the hope that its recognition might simplify the intercourse between the newly formed nations. The primary object of this great work, written during the misery and horrors of the Thirty Years’ war, was expressly to draw attention to these evils and suggest some methods by which the severity of warfare might be mitigated. Grotius originally meant to explain only one chapter of the law of nations:[27] his book was to be called _De Jure Belli_, but there is scarcely any subject of international law which he leaves untouched. He obtained, moreover, a general recognition for the doctrine of the Law of Nature which exerted so strong an influence upon succeeding centuries; indeed, between these two sciences, as between international law and ethics, he draws no very sharp line of demarcation, although, on the whole, in spite of an unscientific, scholastic use of quotation from authorities, his treatment of the new field is clear and comprehensive. Grotius made the attempt to set up an ethical principle of right, in the stead of such doctrines of self-interest as had been held by many of the ancient writers. There was a law, he held, established in each state purely with a view to the interests of that state, but, besides this, there was another higher law in the interest of the whole society of nations. Its origin was divine; the reason of man commanded his obedience. This was what we call international law.[28] [27] See Maine’s _Ancient Law_, pp. 50-53: pp. 96-101. Grotius wrongly understood “Jus Gentium,” (“a collection of rules and principles, determined by observation to be common to the institutions which prevailed among the various Italian tribes”) to mean “Jus _inter_ gentes.” The Roman expression for International Law was not “Jus Gentium,” but “Jus Feciale.”