25. Intrusion of Politics into Religion. (Chapter 3. Alliance of Church and State and its Influence on Public Morals?...) (History of the Christian Church) (Schaff, Philip)

With the union of the church and the state begins the long and tedious history of their collisions and their mutual struggles for the mastery: the state seeking to subject the church to the empire, the church to subject the state to the hierarchy, and both very often transgressing the limits prescribed to their power in that word of the Lord: Render to Caesar the things which are Caesar's, and to God the things that are God's. From the time of Constantine, therefore, the history of the church and that of the world in Europe are so closely interwoven, that neither can be understood without the other. On the one hand, the political rulers, as the highest members and the patrons of the church, claimed a right to a share in her government, and interfered in various ways in her external and internal affairs, either to her profit or to her prejudice. On the other hand, the bishops and patriarchs, as the highest dignitaries and officers of the state religion, became involved in all sorts of secular matters and in the intrigues of the Byzantine court. This mutual intermixture, on the whole, was of more injury than benefit to the church and to religion, and fettered her free and natural development.

Of a separation of religion and politics, of the spiritual power from the temporal, heathen antiquity knew nothing, because it regarded religion itself only from a natural point of view, and subjected it to the purposes of the all-ruling state, the highest known form of human society. The Egyptian kings, as Plutarch tells us, were at the same time priests, or were received into the priesthood at their election. In Greece the civil magistrate had supervision of the priests and sanctuaries. In Rome, after the time of Numa, this supervision was intrusted to a senator, and afterward united with the imperial office. All the pagan emperors, from Augustus to Julian the Apostate, were at the same time supreme pontiffs (Pontifices Maximi), the heads of the state religion, emperor-popes. As such they could not only perform all priestly functions, even to offering sacrifices, when superstition or policy prompted them to do so, but they also stood at the head of the highest sacerdotal college (of fifteen or more Pontifices), which in turn regulated and superintended the three lower classes of priests (the Epulones, Quindecemviri, and Augures), the temples and altars, the sacrifices, divinations, feasts, and ceremonies, the exposition of the Sibylline books, the calendar, in short, all public worship, and in part even the affairs of marriage and inheritance.

Now it may easily be supposed that the Christian emperors, who, down to Gratian (about 380), even retained the name and the insignia of the Pontifex Maximus, claimed the same oversight of the Christian religion established in the empire, which their predecessors had had of the heathen; only with this material difference, that they found here a stricter separation between the religious element and the political, the ecclesiastical and the secular, and were obliged to bind themselves to the already existing doctrines, usages, and traditions of the church which claimed divine institution and authority.