The persistence of Roman law in the Middle Ages, even when the condition of the Italians was most wretched, and when all things seemed to be subject to the law of the Longobard, was maintained with marvellous learning and acumen in the immortal work of Savigny. But, in truth, though public law and penal law might readily be altered under the rule of the conqueror, there was little likelihood that the civil law which, for so many centuries, had filtered into the usages and into the very blood of the Romans, which had regulated the manifold relations of a civilised people and satisfied its countless requirements, should perish utterly beneath the sword of barbarians unconscious of those requirements and not always able to comprehend those relations. Matters of which they were to a great extent ignorant, or as to which they were indifferent, must often have been passed over without notice in the laws framed by the barbarians, or have evaded their action. Various provisions, therefore, of the Roman law--those, for instance, relating to marriage, to succession, and to contract--must often have continued to be applied by the Italians in conformity with ancient usage. This will be more readily understood if we reflect that while the Roman law had become the law of _all_ in those countries in which the Roman conquest had taken deep root, the laws of the barbarians, on the contrary, according to Teutonic usage, always presented a personal character--that is to say, extended only to the people with whom they originated, and were not easily communicated to others. In fact, when, as a consequence of successive invasions, different Germanic tribes, whether independent of each other or in subjection one to another, came together in the same country, each of them continued to be governed by its own peculiar laws. The Romans, on the contrary, regarding their law as universal in character, communicated it to, and imposed it upon all. It was almost the first germ of the greatness and the civilisation of Rome, and for that reason its diffusion was considered the most sacred of duties by this sovereign people. Thus it was that, even under the harshest barbaric oppression, the Roman law continued to be the private law of the Italians in all those cases, and they were not few, in which the German laws failed to notice it, and neither abrogated it directly nor substituted another in its place.