It may indeed be confidently asserted that the conversion of the Roman Empire is so far from being of the nature of a miracle or suspension of the ordinary principles of human nature, that there is scarcely any other great movement on record in which the causes and effects so manifestly correspond. The apparent anomalies of history are not inconsiderable, but they must be sought for in other quarters. That within the narrow limits and scanty population of the Greek States should have arisen men who, in almost every conceivable form of genius, in philosophy, in epic, dramatic and lyric poetry, in written and spoken eloquence, in statesmanship, in sculpture, in painting, and probably also in music, should have attained almost or altogether the highest limits of human perfection—that the creed of Mohammed should have preserved its pure monotheism and its freedom from all idolatrous tendencies, when adopted by vast populations in that intellectual condition in which, under all other creeds, a gross and material worship has proved inevitable, both these are facts which we can only very imperfectly explain. Considerations of climate, and still more of political, social, and intellectual customs and institutions, may palliate the first difficulty, and the attitude Mohammed assumed to art may supply us with a partial explanation of the second; but I suppose that, after all has been said, most persons will feel that they are in presence of phenomena very exceptional and astonishing. The first rise of Christianity in Judæa is a subject wholly apart from this book. We are examining only the subsequent movement in the Roman Empire. Of this movement it may be boldly asserted that the assumption of a moral or intellectual miracle is utterly gratuitous. Never before was a religious transformation so manifestly inevitable. No other religion ever combined so many forms of attraction as Christianity, both from its intrinsic excellence, and from its manifest adaptation to the special wants of the time. One great cause of its success was that it produced more heroic actions and formed more upright men than any other creed; but that it should do so was precisely what might have been expected. To these reasonings, however, those who maintain that the triumph of Christianity in Rome is naturally inexplicable, reply by pointing to the persecutions which Christianity had to encounter. As this subject is one on which many misconceptions exist, and as it is of extreme importance on account of its connection with later persecutions, it will be necessary briefly to discuss it.