Perhaps as important as any of these internal elements of dissolution was that ever-present and ever-developing external menace, the growing power of the barbarian nations. The position of any nation in the historical scale always depends largely upon the relative positions of its neighbour states. Rome early subjugated the other Italian states and then in turn, Sicily, Carthage, and Greece. She held a dominating influence over the nations of the Orient; or, at least, if they held their ground on their own territory, she made it impossible for them to think of invading Europe. Meantime, at the north and west there were no civilised nations to enter into competition with her, much less to dispute her supremacy. For some centuries the peoples of northern Europe could be regarded by Rome only as more or less productive barbarians, interesting solely in proportion as they were sufficiently productive to be worth robbing. But as time went on these northern peoples learned rapidly through contact with the civilisation of Rome. They were, in fact, people who were far removed from barbarism in the modern acceptance of the term. It is possible (the question is still in doubt) that they were of common stock with the Romans; and if their residence in a relatively inhospitable clime had retarded their progress towards advanced civilisation, it had not taken from them the racial potentialities of rapid development under more favourable influences; while, at the same time, the very harshness of their environment had developed in them a vigour of constitution, a tenacity of purpose, and a fearless audacity of mind that were to make them presently most dangerous rivals. It was during the later days of the commonwealth and the earlier days of the empire that these rugged northern peoples were receiving their lessons in Roman civilisation—that is to say, in the art of war, with its attendant sequels of pillage and plundering.[2] Those were hard lessons which the legions of the cæsars gave to the peoples of the north, but their recipients proved apt pupils. Even in the time of Augustus a German host in the Teutoberg Forest retaliated upon the hosts of Varus in a manner that must have brought Rome to a startling realisation of hitherto unsuspected possibilities of disaster.
It has been pointed out that the one hope for the regeneration of Rome under these conditions lay in the possibility of incorporating the various ethnic elements of its wide territories into one harmonious whole. In other words, could Rome in the early day have seen the desirability—as here and there a far-sighted statesman did perhaps see—of granting Roman citizenship to the large-bodied and fertile-minded races of the north, removing thus a prominent barrier to racial intermingling, the result might have been something quite different. We have noted again and again that it is the mixed races that build the great civilisations and crowd forward on the road of human progress. The Roman of the early day had the blood of many races in his veins, but twenty-five or thirty generations of rather close inbreeding had produced a race which eminently needed new blood from without. Yet the whole theory of Roman citizenship set its face against the introduction of this revivifying element. The new blood made itself felt presently, to be sure, and the armies came to be recruited from the provinces. After a time it came to pass that the leaders—the emperors even—were no longer Romans in the old sense of the word. They came from Spain, from Illyricum, and from Asia Minor. Finally the tide of influence swept so strongly in the direction of Illyricum that the seat of Roman influence was transferred to the East, and the Roman Empire entered a new phase of existence. The regeneration was effected, in a measure, by the civilisation of the new Rome in the East; but this was the development of an offspring state rather than the regeneration of the old commonwealth itself. Then in the West the northern barbarians, grown stronger and stronger, came down at last in successive hordes and made themselves masters of Italy, including Rome itself. With their coming and their final conquests the history of old Rome as a world empire terminates.
It is the sweep of events of the five hundred years from the accession of Augustus the first emperor to the overthrow of Romulus Augustulus the last emperor that we have to follow in the present volume. Let us consider in a few words the sources that have preserved the record of this most interesting sequence of events.
THE SOURCES OF IMPERIAL HISTORY