The Popes had the mission to avenge and maintain the rights of man; the heads of public opinion, all feeble though they were, they obtained the strength to dethrone kings with a word and an idea: for a soldier they had but a plebeian, his head protected by a cowl, his hand armed with a cross. The Papacy, marching at the head of civilization, progressed towards the goal of society. Christian men, in all regions of the globe, gave obedience to a priest whose name was hardly known to them, because that priest was the personification of a fundamental truth; he represented in Europe the political independence which was almost everywhere destroyed; in the Gothic world he was the defender of the popular liberties, as in the modern world he became the restorer of science, letters and the arts. The people enrolled itself among his troops in the habit of a mendicant friar. The quarrel between the Empire and the priesthood is the struggle of the two social principles of the middle ages, power and liberty. The Popes, favouring the Guelphs, declared themselves for the governments of the peoples; the Emperors, adopting the Ghibellines, urged the government of the nobles: these were precisely the parts played by the Athenians and Spartans in Greece. Therefore, when the Popes took side with the kings, when they turned themselves into Ghibellines, they lost their power, because they were disengaging themselves from their natural principle, and, for an opposite and yet analogous reason, the monks have seen their authority decrease, when political liberty has returned directly to the peoples, because the peoples have no longer needed to be replaced by the monks, their representatives. Those thrones declared vacant and delivered to the first occupant in the middle ages; those emperors who came on their knees to implore a pontiff's forgiveness; those kingdoms laid under an interdict; an entire nation deprived of worship by a magic word; those anathematized sovereigns, abandoned not only by their subjects, but also by their servants and kindred; those princes avoided like lepers, separated from the mortal race while waiting to be cut off from the eternal race; the food they had tasted, the objects they had touched passed through the flames as things sullied: all this was but the forceful effect of popular sovereignty delegated to and wielded by religion.