The Catholic-Germanic theory of the Middle Ages proper, as regards the civil power in all its functions, from the highest downward, was that of the mere administrator of justice as such; whereas the Roman law regarded the magistrate as the vicegerent of the _princeps_ or _imperator_, in whose person was absolutely vested as its supreme embodiment the whole power of the State.

The Divinity of the Emperors was a recognition of this fact; and the influence of the Roman law revived the theory as far as possible under the changed conditions, in the form of the doctrine of the Divine Right of Kings--a doctrine which was totally alien to the Catholic feudal conception of the Middle Ages.

This doctrine, moreover, received added force from the Oriental conception of the position of the ruler found in the Old Testament, from which Protestantism drew so much of its inspiration.
But apart from this aspect of the question, the new juridical conception involved that of a system of rules as the crystallized embodiment of the abstract "State," given through its representatives, which could under no circumstances be departed from, and which could only be modified in their operation by legal quibbles that left to them their nominal integrity.

The new law could therefore only be administered by a class of men trained specially for the purpose, of which the plastic customary law borne down the stream of history from primitive times, and insensibly adapting itself to new conditions but understood in its broader aspects by all those who might be called to administer it, had little need.

The Roman law, the study of which was started at Bologna in the twelfth century, as might naturally be expected, early attracted the attention of the German Emperors as a suitable instrument for use on emergencies.