Many contemporary writers on International Law tacitly assume that the doctrines of their system, founded on principles of equity and common sense, were capable of being readily reasoned out in every stage of modern civilisation. But this assumption, while it conceals some real defects of the international theory, is altogether untenable, so far as regards a large part of modern history. It is not true that the authority of the Jus Gentium in the concerns of nations was always uncontradicted; on the contrary, it had to struggle long against the claims of several competing systems. It is again not true that the territorial character of sovereignty was always recognised, for long after the dissolution of the Roman dominion the minds of men were under the empire of ideas irreconcileable with such a conception. An old order of things, and of views founded on it, had to decay--a new Europe, and an apparatus of new notions congenial to it, had to spring up--before two of the chiefest postulates of International Law could be universally conceded. It is a consideration well worthy to be kept in view, that during a large part of what we usually term modern history no such conception was entertained as that of "_territorial sovereignty_." Sovereignty was not associated with dominion over a portion or subdivision of the earth. The world had lain for so many centuries under the shadow of Imperial Rome as to have forgotten that distribution of the vast spaces comprised in the empire which had once parcelled them out into a number of independent commonwealths, claiming immunity from extrinsic interference, and pretending to equality of national rights. After the subsidence of the barbarian irruptions, the notion of sovereignty that prevailed seems to have been twofold. On the one hand it assumed the form of what may be called "_tribe_-sovereignty." The Franks, the Burgundians, the Vandals, the Lombards, and Visigoths were masters, of course, of the territories which they occupied, and to which some of them have given a geographical appellation; but they based no claim of right upon the fact of territorial possession, and indeed attached no importance to it whatever. They appear to have retained the traditions which they brought with them from the forest and the steppe, and to have still been in their own view a patriarchal society, a nomad horde, merely encamped for the time upon the soil which afforded them sustenance. Part of Transalpine Gaul, with part of Germany, had now become the country _de facto_ occupied by the Franks--it was France; but the Merovingian line of chieftains, the descendants of Clovis, were not Kings of France, they were Kings of the Franks. The alternative to this peculiar notion of sovereignty appears to have been--and this is the important point--the idea of universal dominion. The moment a monarch departed from the special relation of chief to clansmen, and became solicitous, for purposes of