We have shown the state of the principal powers of Europe during the crusades; it now remains for us to speak of a power which dominated over all the others, and which was as a tie or centre to all the powers;—we mean the authority of the heads of the Church. The popes, as a temporal power and as a spiritual power, presented a singular contrast in the middle ages. As sovereigns of Rome, they had almost no authority, and were often banished from their own states: as heads of Christendom, they exercised an absolute empire to the extremities of the world, and their name was revered wherever the Gospel was preached. It has been said that the popes made the crusades; they who maintain this opinion are far from being acquainted with the general movement which then affected the Christian world; no power on earth could have been able to produce such a great revolution; it only belonged to Him whose will gives birth to and disperses tempests, to throw all at once into human hearts that enthusiasm which silenced all other passions, and drew on the multitude as if by an invisible power. In the first book of this volume we have shown how the enthusiasm for the holy wars developed itself by degrees, and how it broke forth towards the end of the eleventh century, without any other influence but that of the dominant ideas: it led away the whole of society, and the popes were led away as nations of people were; one proof that the sovereign pontiffs did not produce this extraordinary revolution is, that they were never able to revive the spirit of the crusades, when that spirit became extinct among Christian nations. It has likewise been said that the crusades very much increased the authority of the popes; we shall soon see what truth there is in that assertion. Among the causes which contributed to the growth of the pontifical authority, we may name the invasion of the barbarians of the North, who overthrew the empire of the West, and the progress of the Saracens, who would not allow the emperors of the East leisure to turn their attention towards Italy, or even to preserve any domination over that country. The popes thus found themselves freed from two powers upon which they depended; and remained in possession of the city of Rome, which appeared to have no other master. Other circumstances added from that time to the authority of the successors of St. Peter. However it may be, everybody knows that this authority had already made immense progress before the crusades; the head of the most powerful monarchs had already bowed before the thunders of the Vatican; and Christendom seemed to have already adopted the maxim of Gregory VII., that “the pope, in quality of Vicar of Jesus Christ, ought to be superior to every human power.”