The Catholic Church

Learning Objective

  • Outline the role of the Catholic Church in Medieval Europe

Key Points

  • Christianity spread throughout the early Roman Empire despite persecutions due to conflicts with the pagan state religion.
  • When the Western Roman Empire fell in 476, the Catholic Church competed with Arian Christians for the conversion of the barbarian tribes and quickly became the dominant form of Christianity.
  • Monastic communities were centers for learning and preservation of classical culture.
  • Once the cultural and political boundaries of Rome were weakened, Catholicism spread throughout Europe to the Irish, English, Franks, and Goths.



Members of a religious group sent into an area to evangelize or offer ministries of service, such as education, literacy, social justice, health care, and economic development.


The Bishop of Rome and the leader of the worldwide Catholic Church, and the traditional successor to Saint Peter, to whom Jesus is supposed to have given the keys of Heaven, naming him as the “rock” upon which the church would be built.


Conforming to the Christian faith as represented in the creeds of the early church.

Byzantine Empire

Sometimes referred to as the Eastern Roman Empire, was the continuation of the Roman Empire in the East during Late Antiquity and the Middle Ages, when its capital city was Constantinople.

Early History and the Fall of Rome

The history of the Catholic Church begins with the teachings of Jesus Christ, who lived in the 1st century CE in the province of Judea of the Roman Empire. The contemporary Catholic Church says that it is the continuation of the early Christian community established by Jesus.

Christianity spread throughout the early Roman Empire despite persecutions due to conflicts with the pagan state religion. In 313, the struggles of the early church were lessened by the legalization of Christianity by the Emperor Constantine I. In 380, under Emperor Theodosius I, Christianity became the state religion of the Roman Empire by the decree of the emperor, which would persist until the fall of the Western Empire, and later with the Eastern Roman Empire until the fall of Constantinople.

After the destruction of the Western Roman Empire, the church in the West was a major factor in preserving classical civilization, establishing monasteries, and sending missionaries to convert the peoples of northern Europe as far north as Ireland. In the East, the Byzantine Empire preserved Orthodoxy well after the massive invasions of Islam in the mid-7th century.

The Catholic Church in the Middle Ages

After the fall of the Western Roman Empire in 476, the Catholic faith competed with Arianism for the conversion of the barbarian tribes. The 496 conversion of Clovis I, pagan king of the Franks, saw the beginning of a steady rise of the Catholic faith in the West.


Saint Remigius baptizes Clovis

In 530, Saint Benedict wrote his Rule of Saint Benedict as a practical guide for monastic community life, and its message spread to monasteries throughout Europe. Monasteries became major conduits of civilization, preserving craft and artistic skills while maintaining intellectual culture within their schools, scriptoria, and libraries. They functioned as centers for spiritual life as well as for agriculture, economy, and production.

During this period the Visigoths and Lombards moved away from Arianism toward Catholicism. Pope Gregory the Great played a notable role in these conversions and dramatically reformed the ecclesiastical structures and administration, which then launched renewed missionary efforts. Missionaries such as Augustine of Canterbury, who was sent from Rome to begin the conversion of the Anglo-Saxons, and, coming the other way in the Hiberno-Scottish mission, Saints Colombanus, Boniface, Willibrord, and Ansgar, among many others, took Christianity into northern Europe and spread Catholicism among the Germanic and Slavic peoples. Such missions reached the Vikings and other Scandinavians in later centuries. The Synod of Whitby of 664, though not as decisive as sometimes claimed, was an important moment in the reintegration of the Celtic Church of the British Isles into the Roman hierarchy, after having been effectively cut off from contact with Rome by the pagan invaders.

In the early 8th century, Byzantine iconoclasm became a major source of conflict between the eastern and western parts of the church. Byzantine emperors forbade the creation and veneration of religious images as violations of the Ten Commandments. Sometime between 726 and 730 the Byzantine Emperor Leo III the Isaurian ordered that an image of Jesus prominently placed over the Chalke gate, the ceremonial entrance to the Great Palace of Constantinople, be removed, and replaced with a cross. This was followed by orders banning the pictorial representation of the family of Christ, subsequent Christian saints, and biblical scenes. Other major religions in the East, such as Judaism and Islam, had similar prohibitions, but Pope Gregory III vehemently disagreed. Empress Irene, siding with the pope, called for an Ecumenical Council. In 787, the fathers of the Second Council of Nicaea “warmly received the papal delegates and his message.” At the conclusion, 300 bishops, who were led by the representatives of Pope Hadrian I “adopted the Pope’s teaching,” in favor of icons.

Spread of Catholicism Beyond Rome

As the political boundaries of the Roman Empire diminished and then collapsed in the West, Christianity spread beyond the old borders of the Empire and into lands that had never been under Rome.

Beginning in the 5th century, a unique culture developed around the Irish Sea, consisting of what today would be called Wales and Ireland. In this environment, Christianity spread from Roman Britain to Ireland, especially aided by the missionary activity of Saint Patrick. Patrick had been captured into slavery in Ireland and, following his escape and later consecration as bishop, he returned to the isle that had enslaved him so that he could bring them the Gospel. Soon, Irish missionaries such as Saints Columba and Columbanus spread this Christianity, with its distinctively Irish features, to Scotland and the Continent. One such feature was the system of private penitence, which replaced the former practice of penance as a public rite.

Although southern Britain had been a Roman province, in 407 the imperial legions left the isle, and the Roman elite followed. Some time later that century, various barbarian tribes went from raiding and pillaging the island to settling and invading. These tribes are referred to as the “Anglo-Saxons,” predecessors of the English. They were entirely pagan, having never been part of the Empire, and although they experienced Christian influence from the surrounding peoples, they were converted by the mission of Saint Augustine sent by Pope Gregory the Great. Later, under Archbishop Theodore, the Anglo-Saxons enjoyed a golden age of culture and scholarship. Soon, important English missionaries such as Saints Wilfrid, Willibrord, Lullus, and Boniface would begin evangelizing their Saxon relatives in Germany.