Augustine into that _Civitas Terrena_ which he reprobated, and the ideal Kingdom of God became a vulgar earthly monarchy, with all the accompaniments of conquest, fraud, and violence which, according to the great theologian of the West, naturally belonged to such a society. But the glamour of the City of God long remained to dazzle the eyes of gifted and pious men during the earlier Middle Ages, when they contemplated the visible ecclesiastical empire ruled by the Bishop of Rome. The requirements of the practical religion of everyday life were also believed to be in the possession of this ecclesiastical monarchy to give and to withhold. For it was the almost universal belief of mediæval piety that the mediation of a priest was essential to salvation; and the priesthood was an integral part of this monarchy, and did not exist outside its boundaries. “No good Catholic Christian doubted that in spiritual things the clergy were the divinely appointed superiors of the laity, that this power proceeded from the right of the priests to celebrate the sacraments, that the Pope was the real possessor of this power, and was far superior to all secular authority.”(4) In the decades immediately preceding the Reformation, many an educated man might have doubts about this power of the clergy over the spiritual and eternal welfare of men and women; but when it came to the point, almost no one could venture to say that there was nothing in it. And so long as the feeling remained that there might be something in it, the anxieties, to say the least, which Christian men and women could not help having when they looked forward to an unknown future, made kings and peoples hesitate before they offered defiance to the Pope and the clergy. The spiritual powers which were believed to come from the exclusive possession of priesthood and sacraments went for much in increasing the authority of the papal empire and in binding it together in one compact whole. In the earlier Middle Ages the claims of the Papacy to universal supremacy had been urged and defended by ecclesiastical jurists alone; but in the thirteenth century theology also began to state them from its own point of view. Thomas Aquinas set himself to prove that submission to the Roman Pontiff was necessary for every human being. He declared that, under the law of the New Testament, the king must be subject to the priest to the extent that, if kings proved to be heretics or schismatics, the Bishop of Rome was entitled to deprive them of all kingly authority by releasing subjects from their ordinary obedience.(5)