CHURCH

Christianity was a major unifying factor between Eastern and western Europe before the Arab conquests, but the conquest of North Africa sundered maritime connections between the areas. Increasingly the Byzantine Church, which became the Orthodox Church, differed in language, practices, and liturgy from the western Church, which became the Catholic Church. The eastern church used Greek instead of the western Latin. Theological and political differences emerged, and by the early and middle 8th century issues such as iconoclasm, clerical marriage, and state control of the church had widened enough that the cultural and religious differences were greater than the similarities. The formal break came in 1054, when the papacy and the patriarchy of Constantinople clashed over papal supremacy and mutually excommunicated each other, which led to the division of Christianity into two churches – the Roman Catholic Church and the Eastern Orthodox Church.

The ecclesiastical structure of the Roman Empire survived the barbarian invasions in the west mostly intact, but the papacy was little regarded, with few of the western bishops looking to the bishop of Rome for religious or political leadership. Many of the popes prior to 750 were in any case more concerned with Byzantine affairs and eastern theological concerns. The register, or archived copies of the letters, of Pope Gregory the Great, (pope 590–604) survives, and of those more than 850 letters, the vast majority were concerned with affairs in Italy or Constantinople. The only part of western Europe where the papacy had influence was Britain, where Gregory had sent the Gregorian mission in 597 to convert the Anglo-Saxons to Christianity. Other missionary efforts were led by the Irish, who between the 5th and the 7th centuries were the most active missionaries in western Europe, with missionaries going first to England and Scotland and then later onto the continent. Irish missionaries, under such monks as Columba (d. 597) and Columbanus (d. 615), not only founded monasteries but also taught in Latin and Greek and were active authors of secular and religious works.

The Early Middle Ages witnessed the rise of monasticism in the West. The shape of European monasticism was determined by traditions and ideas that originated in the deserts of Egypt and Syria. The style of monasticism that focuses on community experience of the spiritual life, called cenobitism, was pioneered by Pachomius (d. 348) in the 4th century. Monastic ideals spread from Egypt to western Europe in the 5th and 6th centuries through hagiographical literature such as the Life of Anthony. Benedict of Nursia (d. 547) wrote the Benedictine Rule for Western monasticism during the 6th century, detailing the administrative and spiritual responsibilities of a community of monks led by anabbot. Monks and monasteries had a deep effect on the religious and political life of the Early Middle Ages, in various cases acting as land trusts for powerful families, centres of propaganda and royal support in newly conquered regions, bases for mission, and proselytization. In addition, they were the main and sometimes only outposts of education and literacy in a region. Many of the surviving manuscripts of the Romanclassics were copied in monasteries in the early Middle Ages. Monks were also the authors of new works, including history, theology, and other subjects, which were written by authors such as Bede (d. 735), a native of northern England who wrote in the late 7th and early 8th century.

Monastic reform became an important issue during the 11th century, as elites began to worry that monks were not adhering to the rules binding them to a stricy religious life. Cluny Abbey, founded in the Mâcon in 909, was established as part of the Cluniac Reforms, a larger movement of monastic reform in response to this fear. The monastery quickly established a reputation for austerity and rigour. Cluny sought to maintain a high quality of spiritual life by electing its own abbot without interference from laymen, thus maintaining economic and political independence from local lords and placing itself under the protection of the papacy.

Monastic reform inspired change in the secular church. The ideals that it was based upon were brought to the papacy by Pope Leo IX (pope 1049–1054), and provided the ideology of the clerical independence that led to the Investiture Controversy in the late 11th century. This involvedPope Gregory VII (pope 1073–1085) and Emperor Henry IV, who initially clashed over episcopal appointments, disputes that turned into a battle over the ideas of investiture, clerical marriage, andsimony. The emperor saw the protection of the Church as one of his responsibilities as well as wanting to preserve the right to appoint his own choices as bishops within his lands. The papacy, however, insisted on the Church's independence from secular lords These issues themselves remained unresolved after the compromise of 1122 known as the Concordat of Worms. The conflict represents a significant stage in the creation of a papal monarchy separate from and equal to lay authorities. It also had the permanent consequence of empowering German princes at the expense of the German emperors.

The High Middle Ages was a period of great religious movements. Besides the Crusaders and monastic reformers, other people sought to participate in new forms of religious life. New monastic orders were founded, including the Carthusians, the Cistercians, and the military orderssuch as the Knights Templar. These new orders were formed in response to the feeling of the laity that Benedictine monasticism no longer met the needs of the laymen. Laymen and those wishing to enter the religious life wanted to return to the simpler hermetical monasticism of early Christianity or to live an Apostolic life. In the 13th century, mendicant orders – the Franciscans and the Dominicans – who swore vows of poverty and earned their living by begging, were approved by the papacy. Besides the recognized orders, other religious groups such as the Waldensians and the Humiliati attempted to return to the life of early Christianity in the middle 12th and early 13th centuries, but they were condemned as heretical by the papacy. Others joined the Cathars, another heretical movement condemned by the papacy. In 1209, a crusade was preached against the Cathars, the Albigensian Crusade, which in combination with the medieval Inquisition, finally eliminated them.