From this time the Church gained steadily in power and influence. Charles the Great did much to increase its wealth by enforcing the payment of tithes. He insisted that the clergy should be better educated themselves and should do more for the education of the people. In• the 9th century the growing power of the papacy and the weakness of the kings enabled the popes to bring the bishops more directly under their own control. Thus the clergy of western Chris tendom were brought into intimate association with Rome. Latin was the common language of all churchmen. Their feeling of membership in the Church was frequently stronger than any local attachment. Consequently the more able men were equally at home in every country and the Church had a greater unity than any lay power. This all-pervasive Church was the great unifying element amid the divisions of the feudal period.
Investiture Struggle.—After periods of weakness in the first half of the 10th and again in the first half of the 11th century, the Church at Rome was purified and strengthened by the support of the German emperors. About the middle of the 11th century, the strong person alties of Pope Leo IX (q.v.) and of Hildebrand (later Gregory VII) (q.v.) led to a reform movement, and also to an effort to make the popes' power more effective. One feature of this movement was an attempt to secure entire control of appointment to church offices. This brought the papacy into conflict with the kings who considered that they had a right to nom inate the bishops in their own kingdoms. The struggle was most acute between the German emperors and the popes, and resulted in the long investiture conflict, which was ended in 1122 by a compromise. See INVESTITURE.
Roman Empire of the German Nation.— But the investiture struggle was only a single phase in the relations between the empire and the papacy (q.v.). In order to understand this it is necessary to study the fortunes of the em pire after Charles the Great. Under his suc cessors, the emperors had gradually lost their power, so that by the end of the 9th century, the title of emperor had become almost a mean ingless designation, either conferred by a Pope on anyone of whom be wished to make use, or else usurped by any ruler who chanced to be temporarily the strongest personality in Italian affairs. This continued to be the fate of the imperial title until Otto the Great (q.v.) was summoned to Italy, because of the discord and anarchy in the peninsula. In 963 he was crowned emperor, and became the ruler of both Ger many and Italy. Under his son and grandson, Otto II and Otto III, "the Roman Empire of the German nation" was a very effective power in controlling both the imperial lands and the papal policy. After the death of Otto III in 1002, the German rulers paid little attention to Italian affairs until 1046, when Henry III was summoned to Rome because of the contest which was being waged between three rivals for the papal office. For 10 years he wielded a
power similar to that of the Ottos. But at his death, as the heir was a young child, the re formed and strengthened papacy was able to assert its independence. When Henry reached manhood and desired to regain his father's power, the contest began and took the shape of the already mentioned investiture struggle. After the Concordat of Worms (q.v.) there was little conflict until the accession of Frederick Barbarossa (q.v.), who was determined to be emperor in fact as well as in name.
Empire and Papacy.— On the other hand, the papacy was strong and was determined to assert its paramount authority. There ensued a struggle of 100 years between the Hohen staufen emperors and the popes. In spite of the ability of the rulers and the brilliancy of their reigns, the popes triumphed, largely by means of the assistance of the Lombard cities, which had grown rich and powerful and aimed to be independent of the imperial control. The death of Frederick II in 1250 really marks the end of the mediaeval empire as a strong inter national power, although it continued, under a changed form, to be a factor in European poli tics for centuries longer, and came to a close only in the 19th century.
The Crusades.— The increasing power of the popes was also marked by their desire to ex tend their authority over the Eastern Church as well as the Western. This was in part the cause of the Crusades, which were the most important manifestation of the strength and influence of the Church. The spirit of asceti cism (q.v.) had long been inculcated as the most distinguishing mark of Christianity. The consciousness of their own sins and the teach ings of the Church led many to do penance, One of the favorite forms, especially for heinous crimes, was a pilgrimage to some hallowed spot. The most difficult pilgrimage and the one to which greatest sanctity attached was the journey to Jerusalem. In the Ilth century, 116 separate pilgrimages to Jerusalem are re corded, and, in some of these expeditions, hundreds and even thousands took part. Thus attention was directed to the Holy Land. Moreover, in spite of the disorders of the feudal regime, the population was increasing, especially in France. The people were hard pressed to get food, and were anxious for a change of any kind. Consequently, when the Emperor Alexius appealed for aid and Pope Urban II preached the crusade at Clermont thousands took the cross. The movement spread rapidly and affected every country in Europe. Although Jerusalem was in the possession of the Christians for little more than a hundred years, the crusades to the Holy Land, which continued for 200 years, produced great results. In order to understand these, it is necessary now to take up the Byzantine and Moslem civilizations. See CRUSADES.