Theorists who hold it to be a wrong that a nation should belong to a foreign State are therefore in contradiction with the law of civil progress. This law, or rather necessity, which is as absolute as the law that binds society together, is the force which makes us need one another, and only enables us to obtain what we need on terms, not of equality, but of dominion and subjection, in domestic, economic, or political relations. The political theory of nationality is in contradiction with the historic nation. Since a nation derives its ideas and instincts of government, as much as its temperament and its language, from God, acting through the influences of nature and of history, these ideas and instincts are originally and essentially peculiar to it, and not separable from it; they have no practical value in themselves when divided from the capacity which corresponds to them. National qualities are the incarnations of political ideas. No people can receive its government from another without receiving at the same time the ministers of government. The workman must travel with the work. Such changes can only be accomplished by submission to a foreign State, or to another race. Europe has seen two great instances of such conquests, extending over centuries,--the Roman Empire, and the settlement of the barbarians in the West. This it is which gives unity to the history of the Middle Ages. The Romans established a universal empire by subjecting all countries to the authority of a single power. The barbarians introduced into all a single system of law, and thus became the instrument of a universal Church. The same spirit of freedom, the same notions of the State, pervade all the _Leges Barbarorum_, and all the polities they founded in Europe and Asia. They differ widely in the surrounding conditions, in the state of society, in the degree of advancement, in almost all external things. The principle common to them all is to acknowledge the freedom of the Church as a corporation and a proprietor, and in virtue of the principle of self-government to allow religion to develop her influence in the State. The great migration which terminated in the Norman conquests and in the Crusades gave the dominion of the Latin world to the Teutonic chivalry, and to the Church her proper place. All other countries sank into despotism, into schism, and at last into barbarism, under the Tartars or the Turks. The union between the Teutonic races and the Holy See was founded on their political qualities more than on their religious fervour. In modern times, the most pious Catholics have often tyrannised over the Church. In the Middle Ages her liberty was often secured and respected where her spiritual injunctions were least obeyed.