Throughout the early middle ages the Church acquired enormous wealth and Church lands were free from taxation. It was not till a comparatively late period that the payment of tithes was enforced by law. Not infrequently the Church was despoiled by violence, but the balance was more than recovered by fraud. By the time of Charlemagne the clergy were almost exempt from civil jurisdiction and held practically an exclusive authority in matters of religion. The state, however, maintained its temporal supremacy. When the strong hand of Charlemagne was removed ecclesiastical influence increased. It was under Gregory the Great that the Papacy acquired its great supremacy over the Provincial Churches. As the power of the Church grew after the death of Charlemagne, partly from the inclination of weak kings to lean on ecclesiastical support, the Papal claims to authority developed and began to be maintained by the penalties of excommunication and interdict. A period of extreme laxity in the tenth century was to be brought to a close in the eleventh partly by the pressure brought to bear on the Papacy by the Saxon emperors, but still bore by the ambitious resolution of Gregory VII. This remarkable man was determined to assert the complete supremacy of the Holy See over all secular powers. He refused to recognise the right of secular princes to make ecclesiastical appointments within their own dominions; and he emphasised the distinction between the priesthood, as a cast having divine authority, and the laity, by enforcing with the utmost strictness the ecclesiastical law of celibacy, which completely separates the churchman from the normal interests and ambitions which actuate the layman. In the contest between Gregory and the emperor, it seemed for the moment as if the secular power had won the victory; but, in fact, throughout the twelfth century; the claims which Gregory had put forward were becoming practically effective partly from the great influence exercised through the Crusades. These Papal pretensions reached their climax in the great Pope Innocent III., who asserted with practical success the right to pronounce absolutely on all disputes between princes or between princes and their subjects, and to depose those who rejected his authority. Throughout the thirteenth century Rome was once more mistress of the world.