Take another rationalistic explanation of the rise of Christendom. It is common enough to find another critic saying, “Christianity did not really rise at all; that is, it did not merely rise from below; it was imposed from above. It is an example of the power of the executive, especially in despotic states. The Empire was really an Empire; that is, it was really ruled by the Emperor. One of the Emperors happened to become a Christian. He might just as well have become a Mithraist or a Jew or a Fire-Worshipper; it was common in the decline of the Empire for eminent and educated people to adopt these eccentric eastern cults. But when he adopted it, it became the official religion of the Roman Empire; and when it became the official religion of the Roman Empire, it became as strong, as universal, and as invincible as the Roman Empire. It has only remained in the world as a relic of that Empire; or, as many have put it, it is but the ghost of Caesar still hovering over Rome.” This also is a very ordinary line taken in the criticism of orthodoxy, to say that it was only officialism that ever made it orthodoxy. And here again we can call on the heretics to refute it.
The whole great history of the Arian heresy might have been invented to explode this idea. It is a very interesting history often repeated in this connection; and the upshot of it is in that in so far as there ever was a merely official religion, it actually died because it was a merely official religion; and what destroyed it was the real religion. Arius advanced a version of Christianity which moved, more or less vaguely, in the direction of what we should call Unitarianism; though it was not the same, for it gave to Christ a curious intermediary position between the divine and human. The point is that it seemed to many more reasonable and less fanatical; and among these were many of the educated class in a sort of reaction against the first romance of conversion. Arians were a sort of moderates and a sort of modernists. And it was felt that after the