The history of Rome under the Empire presents problems similar to those encountered in the history of the earlier Republic.

Such information as may be directly obtained from literary tradition is not merely without form and colour, but in fact for the most part without substance. The list of the Roman monarchs is just about as trustworthy and just about as instructive as that of the consuls of the republic. The great crises that convulsed the state may be discerned in outline; but we are not much better informed as to the Germanic wars under the emperors Augustus and Marcus, than as to the wars with the Samnites. The republican store of anecdote is very much more decorous than its counterpart under the empire; but the tales told of Fabricius and of the emperor Gaius are almost equally insipid and equally mendacious. The internal development of the commonwealth is perhaps exhibited in the traditional accounts more fully for the earlier republic than for the imperial period; in the former case there is preserved a picture—however bedimmed and falsified—of the changes of political order that were brought at least to their ultimate issue in the open Forum of Rome; in the latter case the arrangements are settled in the imperial cabinet, and come before the public, as a rule, merely in unimportant matters of form. We must take into account, moreover, the vast extension of the sphere of rule, and the shifting of the vital development from the centre to the circumference. The history of the city of Rome widens out into that of the country of Italy, and the latter into that of the Mediterranean world; and of what we are most concerned to know, we learn the least. The Roman state of this epoch resembles a mighty tree, the main stem of which, in the course of its decay, is surrounded by vigorous offshoots pushing their way upwards. The Roman senate and the Roman rulers soon came to be drawn from any other region of the empire just as much as from Italy; the Quirites of this epoch, who have become the nominal heirs of the world–subduing legionaries, have nearly the same relation to the memories of the olden time as our Knights of St. John have to Rhodes and Malta; and they look upon their heritage as a right capable of being turned to profitable account—as an endowment provided for the benefit of the poor that shrink from work.

Any one who has recourse to the so–called authorities for the history of this period—even the better among them—finds difficulty in controlling his indignation at the telling of what deserved to be suppressed, and at the suppression of what there was need to tell. For this epoch was also one productive of great conceptions and far–reaching action. Seldom has the government of the world been conducted for so long a term in an orderly sequence; and the firm rules of administration, which Caesar and Augustus traced out for their successors, maintained their ground, on the whole, with remarkable steadfastness notwithstanding all those changes of dynasties and of dynasts, which assume more than due prominence in a tradition that looks merely to such things, and dwindles erelong into mere biographies of the emperors. The sharply–defined sections, which—under the current conception, misled by the superficial character of such a basis—are constituted by the change of rulers, pertain far more to the doings of the court than to the history of the empire. The carrying out of the Latin–Greek civilising process in the form of perfecting the constitution of the urban community, and the gradual bringing of the barbarian or at any rate alien elements into this circle, were tasks, which, from their very nature, required centuries of steady activity and calm self–development; and it constitutes the very grandeur of these centuries that the work once planned and initiated found this long period of time, and this prevalence of peace by land and sea, to facilitate its progress. Old age has not the power to develop new thoughts and display creative activity, nor has the government of the Roman empire done so; but in its sphere, which those who belonged to it were not far wrong in regarding as the world, it fostered the peace and prosperity of the many nations united under its sway longer and more completely than any other leading power has ever succeeded in doing. It is in the agricultural towns of Africa, in the homes of the vine–dressers on the Moselle, in the flourishing townships of the Lycian mountains, and on the margin of the Syrian desert that the work of the imperial period is to be sought and to be found. Even now there are various regions of the East, as of the West, as regards which the imperial period marks a climax of good government, very modest in itself, but never withal attained before or since; and, if an angel of the Lord were to strike the balance whether the domain ruled by Severus Antoninus was governed with the greater intelligence and the greater humanity at that time or in the present day, whether civilisation and national prosperity generally have since that time advanced or retrograded, it is very doubtful whether the decision would prove in favour of the present. But, if we find that this was the case, we ask of our surviving books for the most part in vain how it came to be so. They no more give an answer to this question than the traditional accounts of the earlier republic explain the mighty phenomenon of the Rome, which, in the footsteps of Alexander, subdued and civilised the world.

The one void as little admits of being filled up as the other. But it seemed worth our making the attempt for once to turn away our eyes from the pictures of the rulers with their bright or faded, and but too often falsified, colours, as well as from the task of linking into a semblance of chronological order fragments that do not fit each other; and, instead of this, to collect and arrange such materials as tradition and the monuments furnish for a description of the Roman provincial government. It seemed worth while to collate the accounts accidentally preserved by the one or by the other, to note traces of the process of growth embedded in its results, and to view the general institutions in their relation to the individual provinces, along with the conditions given for each by the nature of the soil and of the inhabitants, so as to work out by the imagination—which is the author of all history as of all poetry—if not a complete picture, at any rate a substitute for it.

In this attempt I have not sought to go beyond the epoch of Diocletian. A summary glance, at the utmost, into the new government which was then created may fitly form the keystone of this narrative; to estimate it fully would require a separate narration and another frame for its setting—an independent historical work, carried out in the large spirit and with the comprehensive glance of Gibbon, but with a more accurate understanding of details. Italy and its islands have been excluded; for the account of these cannot be dissociated from that of the general government of the empire. The external history, as it is called, of the imperial period is dealt with as an integral part of the provincial administration; what we should call imperial wars were not carried on under the empire against those outside of its pale, although the conflicts called forth by the rounding off, or the defence, of the frontier sometimes assumed such proportions as to make them seem wars between two powers similar in kind, and the collapse of the Roman rule in the middle of the third century, which for some decades seemed as though it were to become its definitive end, grew out of the unhappy conduct of frontier–defence at several places simultaneously. Our narrative opens with the great work of pushing forward, and of regulating the frontier towards the north, which was partly carried out and partly failed under Augustus. At other points we bring together the events that occurred on each of the three chief arenas for frontier–defence—the Rhine, the Danube, the Euphrates. The remainder of the narrative is arranged according to provinces. Charms of detail, pictures of feeling, sketches of character, it has none to offer; it is allowable for the artist, but not for the historian, to reproduce the features of Arminius. With self–denial this book has been written; and with self–denial let it be read.