Early Middle Ages

The Christianization of Europe: How the Continent Was Won for Christ

The slow, uneven Christianization of Europe between the fifth and the eleventh centuries, from the Anglo-Saxons and Franks to the Slavs, Norse, and Hungarians.

In-depth article

By the year 1000, virtually every people between the Atlantic and the Russian steppes had been baptized in the name of Christ. The Anglo-Saxons, the Franks, the Visigoths, the Lombards, the Irish, the Picts, the Germans, the Frisians, the Saxons, the Avars, the Bulgars, the Serbs, the Moravians, the Bohemians, the Poles, the Rus, the Hungarians, the Danes, the Norwegians, the Swedes, and the Icelanders had all, in the space of five centuries, become Christian. The Christianization of Europe was one of the most important transformations in human history, and it was the work of the early Middle Ages.

The process was neither smooth nor uniform. It was driven by royal decisions, monastic missions, political alliances, and at times violent coercion, and it produced enduring tensions between Christian and non-Christian populations, especially in frontier regions. Yet by the end of the period, the Christianization of Europe was essentially complete, and the framework of medieval Christendom was in place.

The early conversions

The Christianization of the Germanic peoples had begun in late antiquity, with the conversion of the Franks under Clovis (c. 496) and the Visigoths under Reccared (587). The Franks were the first of the major Germanic peoples to accept Catholic Christianity, and the conversion of Clovis is traditionally dated to his baptism by Remigius of Reims on Christmas Day, 496. The conversion was politically significant: it aligned the Franks with the Catholic church of Gaul, set the stage for the Frankish domination of the Western church, and laid the foundations for the Merovingian dynasty that would rule Gaul for the next two centuries.

The Visigoths, who had been Arian Christians since the fourth century, converted to Catholic Christianity under King Reccared in 587, at the Third Council of Toledo. The conversion was the result of decades of negotiation between the Visigothic kings and the Catholic bishops of Spain, and it was politically motivated: by becoming Catholic, Reccared hoped to unify his kingdom under a single church. The conversion did not, however, prevent the Muslim conquest of Spain in 711, but it did shape the religious culture of the Iberian Peninsula for centuries.

The Lombards, the last of the major Germanic peoples to enter the Western Roman Empire, were converted in stages. The Lombard kings had been Arian, but the Catholic bishops of Italy were able to bring large numbers of Lombards into the Catholic church by the seventh century. The conversion was a complex process, involving political alliances, missionary activity, and the slow work of institution-building. The Lombard dukes of Benevento, Spoleto, and Friuli remained semi-independent for centuries, and the Lombard kingdom would not be fully integrated into the Catholic church until the eleventh.

The Anglo-Saxon mission

The most carefully documented missionary movement of the early Middle Ages was the conversion of the Anglo-Saxons. The Anglo-Saxons had been pagan when they arrived in Britain in the fifth century, and the British church - already weakened by the Roman withdrawal and the Saxon incursions - was unable to evangelize them. The mission that eventually converted the Anglo-Saxons was sent from Rome, at the instigation of Pope Gregory the Great. In 596, Gregory dispatched a group of monks led by the Augustine of Canterbury to Kent, where King Æthelberht had a Christian wife, Bertha of Paris. Augustine landed in 597, and within a few years he had baptized the king and established the first English bishopric at Canterbury.

The mission to the Anglo-Saxons was a model for the missionary movement of the early Middle Ages. Augustine’s strategy was to work through the existing political structure, converting the king and then supporting the establishment of bishoprics and monasteries in his kingdom. The missionaries were monks, sent by the pope, who traveled with the protection of the king and the support of his court. The strategy was successful: by the time of Augustine’s death in 604, Christianity had been established in Kent, and within a generation it had spread to Essex, East Anglia, and Northumbria. The Northumbrian church, evangelized by monks from Iona led by Aidan, became the center of a remarkable flowering of Christian learning and art, exemplified by figures such as Bede, Cuthbert, and the illuminators of the Lindisfarne Gospels.

The mission to the Anglo-Saxons was not without its difficulties. The Synod of Whitby in 664, which decided between the Roman and Irish traditions on the computation of Easter, was only one of many disputes that shaped the early English church. The pagan reaction under kings such as Penda of Mercia, the Viking attacks of the ninth and tenth centuries, and the political fragmentation of the Anglo-Saxon kingdoms all threatened the work of the missionaries. Yet by the time of the Norman Conquest in 1066, England was a thoroughly Christian kingdom with a sophisticated ecclesiastical infrastructure, and it was about to send out its own missionaries to Denmark, Norway, and beyond.

The continental missions

The English missionaries who had converted their own island soon turned to the conversion of the continent. The most famous of them was Boniface, originally named Winfrid, who left England in 716 to evangelize the Frisians and the Germans. Boniface was supported by the papacy and by the Carolingian mayors of the palace, and he worked systematically to establish bishoprics, monasteries, and schools across the regions east of the Rhine. His most famous act was the felling of Donar’s Oak at Geismar in 723, an event that became symbolic of the victory of Christianity over Germanic paganism.

Boniface’s work was continued by his disciples, who established a network of bishoprics and monasteries in the German Rhineland, Hesse, Thuringia, and Bavaria. The great abbeys of Fulda, Reichenau, St. Gall, and Corvey were founded in this period, and they became the chief instruments of Christianization in the German lands. The archbishoprics of Mainz, Cologne, Trier, Salzburg, and Hamburg-Bremen were also established or reorganized in this period, and they became the principal sees of the German church.

The Christianization of the Saxons, the most stubborn of the Germanic peoples, was a much more violent process. The Saxons resisted the missionaries sent from England and from the Frankish church, and the Carolingian rulers, especially Charlemagne, eventually responded with military campaigns of forced conversion. The Saxon Wars (772-804) culminated in the massacre of the Verden in 782, when Charlemagne is said to have ordered the execution of 4,500 Saxon prisoners who refused to convert. The Saxon capitulation of 804, in which the surviving Saxons accepted baptism and the payment of tithes, marked the end of the independent Saxon religion.

The Christianization of the Slavic peoples

The Christianization of the Slavic peoples was one of the most important events of the ninth and tenth centuries. The Slavs had been evangelized in part by the Roman Catholic mission of Cyril and Methodius to Moravia in 863, and in part by the Byzantine mission to Bulgaria, Serbia, and Rus. The two streams of missionary activity produced two distinct forms of Slavic Christianity: the Catholic Slavs of Bohemia, Poland, and (briefly) Croatia, who used the Latin liturgy; and the Orthodox Slavs of Bulgaria, Serbia, and Rus, who used the Old Church Slavonic liturgy developed by Cyril and Methodius.

The mission of Cyril and Methodius was one of the most remarkable cultural projects of the early Middle Ages. Cyril (originally named Constantine) was a Byzantine scholar who had worked among the Khazars and the Arabs before being sent to Moravia by the Byzantine emperor. Together with his brother Methodius, he developed an alphabet for the Slavonic language - the Glagolitic alphabet, later replaced by the Cyrillic - and translated the Bible, the liturgy, and the works of the Church Fathers into Slavonic. The mission was politically contested: the Frankish clergy, supported by the Carolingian rulers, opposed the use of Slavonic in the liturgy, and the mission to Moravia was eventually expelled. Yet the work of Cyril and Methodius laid the foundation for the conversion of Bulgaria, Serbia, and Rus, and Old Church Slavonic became the literary language of Slavic Orthodoxy.

The Christianization of Bulgaria in 864, under Tsar Boris I, was politically motivated: Boris accepted baptism in return for Byzantine recognition of Bulgarian independence. The conversion of Serbia followed in the ninth century, and the conversion of Rus in 988, under Prince Vladimir of Kiev, was a defining moment in the history of Eastern Europe. Vladimir is said to have considered Judaism, Islam, Latin Christianity, and Greek Orthodoxy before choosing the Byzantine rite, partly because of the beauty of the liturgy at Hagia Sophia. The “baptism of Rus” - the mass baptism of the citizens of Kiev in the Dnieper - marked the beginning of a Christian civilization that would eventually extend to the Volga, the Urals, and beyond.

The conversion of Scandinavia

The Christianization of Scandinavia was the last great missionary movement of the early Middle Ages. The Norse had been evangelized in part by the mission of Ansgar, the “Apostle of the North,” who worked in Denmark and Sweden in the ninth century. Ansgar was a monk from the monastery of Corbie, sent to Scandinavia by Louis the Pious, and he established a small Christian community at Birka in Sweden. Yet the work of Ansgar was interrupted by pagan reaction, and it was not until the tenth and eleventh centuries that Scandinavia was thoroughly Christianized.

The Christianization of Denmark was achieved in the tenth century, largely through the work of Harald Bluetooth, who was baptized c. 965. The conversion of Norway was achieved in the eleventh century, through the work of Olaf Tryggvason (995-1000) and Olaf Haraldsson (St. Olaf, 1015-1028), who used both persuasion and force. The conversion of Sweden was slower and more contested, and the pagan temple at Uppsala remained a center of Norse religion until the late eleventh century. The conversion of Iceland was achieved in 1000, by a decision of the Althing that declared Christianity the official religion while permitting the private worship of the old gods. The conversion of Greenland and the attempted conversion of Vinland (Newfoundland) followed in the eleventh century, when Leif Erikson and other Icelandic Christians attempted to bring Christianity to the Norse settlements in the New World.

The Christianization of Scandinavia was closely tied to the Viking Age. The Norse raids and settlements had brought the Scandinavians into contact with Christian Europe, and many Vikings had accepted baptism during their campaigns. The growth of the Norse trade networks, the establishment of Norse settlements in Christian lands, and the political consolidation of the Scandinavian kingdoms all contributed to the gradual Christianization of the region. By the end of the eleventh century, Scandinavia was a Christian region, and the Norse had become a major source of missionaries, crusaders, and kings for the rest of Europe.

The mechanics of conversion

The Christianization of Europe was not simply a matter of baptism. It involved the building of churches, the establishment of bishoprics, the endowment of monasteries, the creation of Christian law codes, the suppression of pagan practices, and the slow transformation of custom and belief. The work of Christianization was therefore a work of institution-building as much as of evangelism. Monasteries became the chief instruments of religious, cultural, and economic life; bishoprics were the basic units of ecclesiastical administration; and the Christianization of customary law - in the Leges of the Germanic peoples - was one of the most important features of the early medieval legal order.

The mechanics of conversion varied from region to region. In some cases, the conversion was led by kings, who would accept baptism and then support the establishment of Christian institutions. In other cases, it was led by monks, who would establish monasteries and then work to convert the surrounding population. In still other cases, it was led by foreign missionaries, sent by the pope or by a major monastic house. The process could take generations, and it could involve periods of pagan reaction, syncretism, and even violent persecution. Yet by the year 1000, virtually all of Europe had been Christianized, and the framework of medieval Christendom was in place.

Further reading

  • Robert Bartlett, The Making of Europe: Conquest, Colonization, and Cultural Change, 950–1350 (Princeton University Press, 1993).
  • Richard Fletcher, The Conversion of Europe: From Paganism to Christianity, 371–1386 (HarperCollins, 1997).
  • Ian Wood, The Missionary Life: Saints and the Evangelisation of Europe, 400–1050 (Longman, 2001).