Albericus Gentilis
Modern international law is generally regarded as beginning with the Peace of Westphalia in 1648. But it is necessary to go much further back in the history of the world for the beginnings of the law governing the intercourse of nations. The Greek states had a rudimentary inter-state law that regulated their relations. Thus they practiced arbitration in a way among themselves: they recognized the sanctity of the person of heralds, and they followed other recognized customs in their dealings one with another. When Rome and Carthage and other nations were struggling for the mastery of the world, the beginnings of a law of nations were recognized and practiced between them. Upon, however, practically all the known world coming under the sway of imperial Rome, all possibility as well as need of a law of nations was wanting, and as a result the faltering beginnings of an international law as recognized among the Greek states and then by the Powers surrounding the Mediterranean, were extinguished by the extension of the Pax Romana to all the known world.