period, cannot be carried out completely as regards various sections, especially for the period from Gallienus to Diocletian; and in these cases the general picture, which still remains to be given, will have to supply what is wanting. If an historical work in most cases acquires a more vivid clearness by an accompanying map, this holds in an especial degree true of our survey of the Empire of three Continents according to its provinces, and but few of its readers can have in their hands maps adequate for the purpose. These will accordingly be grateful, along with me, to my friend Dr. Kiepert, for having, in the manner and with the limits suggested by the contents of these volumes, annexed to them, first of all, a sheet presenting a general outline of the _Orbis Romanus_, which serves moreover in various respects to supply gaps in those that follow, and, in succession, nine special maps of the several portions of the empire drawn--with the exception of sheets 5, 7, 8, 9--on the same scale. The ancient geographical names occurring in the volumes, and the more important modern ones, are entered upon the maps; names not mentioned in the volumes are appended only, in exceptional cases, as landmarks for the reader's benefit. The mode of writing Greek names followed in the book itself has been displaced by the Latinising spelling--for the sake of uniformity--in several maps in which Latin names preponderate. The sequence of the maps corresponds on the whole to that of the book; only it seemed, out of regard for space, desirable to present on the same sheet several provinces such as, _e.g._ Spain and Africa. PREFATORY NOTE In the fifth volume of his _Roman History_, issued in 1885, Mommsen described the Roman provinces as they were during the first three centuries of our era. It has been called, by one specially qualified to judge, Otto Hirschfeld, the best volume of the whole work. It is indeed a wonderful book. Here Mommsen summed up with supreme mastery a vast and multifarious mass of detail. Thousands of inscriptions yielded up their secrets; all scattered archaeological discoveries found recognition; the vast and dim areas of the provinces took definite shape and colour. Now at length it became easy to discern the true character of the Roman Empire. Our horizon broadened beyond the backstairs of the Palatine and the benches of the Curia to the wide lands north and east and south of the Mediterranean, and we began to realise the achievements of the Empire--its long and peaceable government of dominions extending into three continents, its gifts of civilisation, language, and citizenship to almost all its subjects, its creation of a stable and coherent order out of which rose the Europe of to-day. The old theory of an age of despotism and decay was overthrown. The believer in human nature could now feel confident that, whatever their limitations and defects, the men of the Empire wrought for the progress and happiness of the world.