its influence over adoptions, now no longer restricted to the small circle of relations; they uniformly countenanced formal adoption (_arrogatio_) which was somewhat difficult owing to the difficulty of a father's becoming a subordinate member of another family; they considered emancipation as a benefit and gave to legitimization "by a subsequent marriage" all the efficacy of solemn wedlock. The _imperium paternum,_ as an arrogant title seeming to detract from the imperial majesty, was altered into _patria potestas._ The humane tendencies of the monarchs extended moreover to that part of the ancient "family" which consisted of slaves: for the emperors restrained the cruelty of masters towards these, and benefited them by increasing the force and decreasing the solemnity of manumission; and citizen rights, which were given originally only to distinguished foreigners who had deserved well of the Roman people, were granted to every one born in Rome, even of a slave father provided his mother were free or enfranchised. Punishments were also made milder, and the monarchs distinguished themselves by the gracious title of "clement." The letter of the law always tended to be more freely interpreted in the light of natural equity, and it may be said that Constantine absolutely cancelled the letter when he laid down the principle that any particular motive of equity should override the law. Thus was attained the precise opposite of the _"privilegia ne irroganto"_ of the Twelve Tables ("that no exceptions be made"): all privileges were exceptions to the law dictated by some particular merit in the facts which lifted them out of the sphere of legal generalisations. The restriction of rights to particular peoples was by degrees abolished: under Caracalla the whole Roman world was converted into a single Rome, since great monarchs desire the whole world to become one city, according to the thought of Alexander the Great, when he said that for him all the world was a single city of which his phalanx was the citadel. The praetor's edict gives place, under Hadrian, to the "perpetual edict" of Salvius Julianus, almost exclusively composed of provincial edicts. With monarchy, the natural law of races gives place to the natural law of nations; and hence this political, social and juridical form is the most suitable to human nature at its fullest rational development. Here too, as we have already had occasion to remark, we reach again after a long process the unity which existed in the person of the primitive father under domestic monarchy; and the course of national history must be considered as absolutely complete. To go further is impossible: the only possibility, at this stage of the highest human civilisation and refinement, is corruption, the return of barbarism as a "barbarism of reflection" and a relapse into a kind of new state of nature, to return once more into a new and heroic barbarism. CHAPTER XVIII THE RETURN OF BARBARISM: THE MIDDLE AGES