The only facts connected with the reigns of these emperors which need be noticed here are, that in the reign of Claudius, Britain was added to the Roman dominion; that under the great Trajan, the Empire was still farther extended; and that under Caracalla, the Roman franchise was extended to all the free inhabitants of the Empire. The vices of such emperors as Caligula, Nero, Commodus, Caracalla, and Heliogabalus, may pass unnoticed, as may also the military achievements of some of the later emperors. The reign of Diocletian, however (A. D. 248-305), constitutes an epoch in the history of the Empire. Finding the unwieldy mass too great for the administration of a single individual, he divided it between himself and his colleague Maximian, assigning to Maximian the western or Latin-speaking nations, and retaining the East in his own hands. Under each emperor there was to be a royal personage called Cæsar, who was to govern part of that emperor’s section of the Empire, and afterwards succeed him in the chief dignity. This arrangement did not last long; and after various subdivisions of the Empire, and struggles between emperors and Cæsars, the whole was reunited under Constantine the Great (A. D. 306-337). Under this remarkable man Christianity was established as the religion of the Empire. During the three centuries which had elapsed between the crucifixion of Christ――which took place in the nineteenth year of the reign of Tiberius――and the accession of Constantine to the supreme government of the whole Empire, the new religion had been silently but surely spreading itself; first among the Jews, then among the Greek or eastern, and lastly among the Latin or western Gentiles. It had been subjected to numerous persecutions, some local, and others general, over the whole Empire; but had, nevertheless, made such progress, that it is calculated that in Constantine’s reign about a twentieth part of the whole population of the Empire were professed Christians, while even over the nineteen-twentieths who continued in polytheism, the indirect influence of Christianity had been immense. Led to embrace Christianity himself, although with a considerable tincture of polytheistic superstition, Constantine gave his imperial recognition to the already fully-organized ecclesiastical system of the Christians, with its churches, presbyters, bishops, metropolitans. The civil ban having thus been removed from the profession of Christianity, it began to prevail in form, as it already did in fact, over the heterogeneous polytheism of the Empire.