The Christianization of Scandinavia refers to the process of conversion to Christianity of the Scandinavian people, starting in the 8th century with the arrival of missionaries in Denmark; it was at least nominally complete by the 12th century, although the Samis remained unconverted until the 18th century.
In fact, although the Scandinavians became nominally Christian, it took considerably longer for actual Christian beliefs to establish themselves among the people. The old indigenous traditions that had provided security and structure since time immemorial were challenged by ideas that were unfamiliar, such as original sin, the Incarnation, and the Trinity. Archaeological excavations of burial sites on the island of Lovön near modern-day Stockholm have shown that the actual Christianization of the people was very slow and took at least 150-200 years, and this was a very central location in the Swedish kingdom. Thirteenth century runic inscriptions from the bustling merchant town of Bergen in Norway show little Christian influence, and one of them appeals to a Valkyrie. At this time, enough knowledge of Norse mythology remained to be preserved in sources such as the Eddas in Iceland.
It may be a sign of the slowness of the conversion that many elements of the old faith, even several of the gods, remained part of Scandinavian folklore until modern times. Moreover, the early Christianity that established itself was a syncretic brand different from that of modern days. It was a Germanic Christianity in which Jesus was a conquering warlord.
Recorded missionary efforts in what is today Denmark started with Willibrord, Apostle to the Frisians, who preached in Schleswig, which at the time was part of Denmark. All that is recorded is that he went north from Frisia sometime between 710 and 718 during the reign of King Agantyr (Latin:Ogendus). Agantyr is described as "hideous as a beast and hard as granite. Williborord and his companions had little success: the king was respectful but had no interest in changing his beliefs. Agantyr did permit 30 young men to return to Frisia with Willibrord with the intent to educate them and perhaps convince some of them to join his efforts to bring Christianity to the savage Danes. A century later Ebbo, Archbishop of Reims and Willerich, later Bishop of Bremen, baptized a few persons during their 823 visit to Denmark. He returned to Denmark twice to prosyletize but without any recorded success.
In 826, the King of Jutland Harald Klak was forced to flee from Denmark by Horik I, Denmark's other king. Harald went to Emperor Louis I of Germany to seek help getting his lands in Jutland back. Louis I offered to make Harald Duke of Frisia if he would give up the old gods. Harald agreed, and his family and the 400 Danes with him were baptized in Ingelheim am Rhein. When Harald eventually returned to Jutland, Emperor Louis assigned the monk Ansgar to accompany him and oversee Christianity among the converts. Harald Klak was forced from Denmark by King Horik I again, so Ansgar left Denmark and focused his efforts on the Swedes. In 831 the Archdiocese of Hamburg was founded and assigned responsibility for proselytizing Scandinavia.
Horik I sacked Hamburg in 845 where Ansgar had become the archbishop. The seat of the archdiocese was transferred to Bremen. In a strange twist of events, Ansgar returned to Denmark in 860 and won over the trust of King Horik I who gave him land in Hedeby Schleswig for the first Christian chapel in Denmark. A second church was founded a few years later in Ribe on Denmark's west coast. Ribe was an important trading town, and as a result, Ribe was made a diocese in 948, a part of the Archdiocese of Hamburg-Bremen under its first bishop, St. Leofdag who was murdered that year while crossing the Ribe River.
The spread of Christianity in Denmark occurred intermittently. Danes encountered Christians when they participated in Viking raids from the 800s to the 1060s. Their contempt for Christian teaching, sites, and those who lived a religious life was notorious. Danes were still tribal in the sense that local chief determined attitudes towards Christianity and Christians for their clan and kinsmen. Bringing Christian slaves or future wives back from a Viking raid brought large numbers of ordinary Danes into close contact with Christians for perhaps the first time.
As the chiefs and kings of Denmark became involved in the politics of Normandy, England, Ireland, France, and Germany, they adopted a kinder attitude toward their Christian subjects. In some cases the conversion of the chief or king appears to be purely political to assure an alliance or prevent powerful Christian neighbors from attacking. There were instances of a chief (Danish: jarl) or one of the kings was followed by wholesale conversions. In a few instances conversion was brought about by trial-by-ordeal miracles wrought by saintly Christians in the presence of the king or other great men of the time.
Christian missionaries recognized early on that the Danes did not worship stone or wooden idols as the north Germans or some Swedes did. They could not simply destroy an image to prove that Christ was a superior god. The great religious sites at Viborg, Leira, Lund, and Odense were also the location of Denmark's great assembly places (Danish: landsting). Religious sites in Denmark were often located at sacred springs, magnificent beech groves, or isolated hilltops. Missionaries simply asked to build chapels in those places. Over time the religious significance of the place transferred itself to the chapel.
Even after becoming Christian, Danes blended the two beliefs systems together. Families who lived close to the earth did not want to offend the local spirits (Danish: landvætter), so offerings were left just as they had been in pre-Christian days. Sacred springs (Danish: kilder) were simply consecrated to one of the local saints associated with the spring and life went on much as it had before. Christian missionaries were able to help the process along by locating churches on or near sacred places, in some cases actually using wood from the sacred groves for church construction. Thor's hammer sign was easily absorbed by the cross.
Denmark has several saints, both officially canonized or revered by locals as saints. Often these saints derive their veneration from deeds associated with the Christianization of Denmark. Viborg has St Kjeld, Aarhus has St Niels (also called St Nickolas), Odense has St Canute (Danish: Sanct Knud). Others include Canute Lavard, Ansgar, St Thøger of Vendsyssel, St Wilhelm, St Leofdag of Ribe, and others gave their lives and efforts to the task of making the Danes Christian.
King Gorm the Old (Danish: den Gamle), who was known in his lifetime as Gorm the Sleepy (Danish: Løge), was the first king of all of Denmark. Until his day, Danish kings were local kings without influence over all the Danes. Denmark consisted of Jutland and Schleswig and Holstein all the way down to the Eider River, the main islands of Zealand, Funen, Langeland, the nearby lesser islands, and southern Sweden (Danish: Skåne). Gorm was said to be "hard and heathen", but Queen Thyra's influence permitted Christians to live more or less without trouble. Gorm and Queen Thyra's son, King Harald Bluetooth (c. 911 - c. 986) boasted on one of the stones at Jelling that he had "made (Danish: gjorde) the Danes Christian". But Harald remained steadfstly pagan although he allowed public preaching by Christian missionaries as early as 935 in his lands before he became king. King Harald Bluetooth (Danish: Blåtand) finally converted in 960 when the Frisian monk Poppo held a fire-heated lump of iron in his hand without injury. King Harald and Queen Gunnild and their son, Sweyn Forkbeard grudgingly agreed to be baptized. There was also a political reason for conversion. German histories record Harald being baptized in the presence of Emperor Otto I, Sweyn Forkbeard's godfather. One consequence of his conversion is that Danish kings abandoned the old royal enclosure at Jelling and moved their residence to Roskilde on the island of Zealand.
Sweyn rebelled against his father, who spent an inordinate amount of time and money raising a great stone at Jelling to commemorate his accomlishments. One day King Harald asked a traveler if he had ever seen human beings move such a heavy load. "I have seen Sweyn drag all of Denmark away from you, sir. Judge for yourself which of you bears the heavier weight. Harald left the stone lying in the path, realizing at last that Svend had nearly succeeded in stealing the whole kingdom. Several battles brought the rebellion to stalemate, but in 985 Harald was mortally wounded by an arrow. Later his remains were buried in the little timber church at Roskilde, then Denmark's capital. His remains are supposed to be walled up in one of the pillars of Roskilde Cathedral.
Sweyn Forkbeard tried to wrest control of the church in Denmark away from the Holy Roman Empire and as a result was slandered by German historians of his day. He has been accused of relapsing from his Christian beliefs and persecuting Christians in England. In fact Sweyn gave land to the large cathedral at Lund to pay for the maintenance of the chapter. His army destroyed Christian churches in England as part of his invasion following the St Brice's Day massacre of Danes organized by Aethelred. But when Sweyn became King of England and of Denmark, politics required that he show a kinder face toward the church which had opposed him Denmark.
Another Christianizing influence was the mass emigration of Danes to England and Normandy in the Viking years. Thousands of Danes settled in east central England and in northern France displacing or intermarrying with the locals who were all Christian. Once part of a Danish clan became Christian, it often meant that the rest of the family's view toward Christianity softened.
By the early 11th century, certainly during the reign of Canute IV, Denmark can be said to be a Christian country. St Canute was murdered inside St Albans Church in 1085 after nobles and peasants alike rebelled at his enforcing the tithe to pay for the new monasteries and other ecclesiatical foundations which were introduced into Denmark for the first time during his reign. Both the institutions and the tax were considered foreign influences, and Canute's refusal to use the regional assemblies (Danish: landsting) as was customary to establish new laws, resulted not only in his own death, but that of his brother, Prince Benedict, and seventeen other housecarls. In many ways the canonization of St Canute in 1188 marks the triumph of Christianity in Denmark. When St Canute's remains were moved into Odense Cathedral, the entire nation humbled itself with a three day fast. Although he was not the first Dane to be made a saint, it was the first time for a king, the symbol of a more or less united Denmark was recognized as an example worthy of veneration by the faithful.
From that time until 1536 when Denmark became a Lutheran country under the King (or Queen) of Denmark as the titular head of the Danish National Church, (Danish: Folkekirke) the struggle between the power of the king and nobles and the church would define much of the course of Danish history.
The first recorded attempts at spreading Christianity in Norway were made by King Haakon the Good (reigned 934-961), who was raised in England. His efforts were unpopular and were met with little success. The subsequent King Harald Greyhide (reigned 961–976), also a Christian, was known for destroying pagan temples but not for efforts to popularize Christianity.
He was followed by the staunchly pagan Haakon Sigurdsson Jarl (reigned 971-995) who led a revival of paganism with the rebuilding of temples. When Harold I of Denmark attempted to force Christianity upon him around 975, Haakon broke his allegiance to Denmark. A Danish invasion force was defeated at the battle of Hjörungavágr in 986.
In 995 Olaf Tryggvason would become King Olaf I of Norway. Olaf had raided various European cities and fought in several wars. In 986 however, he (supposedly) met a Christian seer on the Isles of Scilly. This seer told him:
The legend continues that, as the seer foretold, Olaf was attacked by a group of mutineers upon returning to his ships. As soon as he had recovered from his wounds, he let himself be baptized. He then stopped raiding Christian cities and lived in England and Ireland. In 995 he used an opportunity to return to Norway. When he arrived, Haakon Jarl was already facing a revolt, and Olaf Tryggvason could convince the rebels to accept him as their king. Haakon Jarl was later betrayed and killed by his own slave, while he was hiding from the rebels in a pig sty.
Olaf I then made it his priority to convert the country to Christianity using all means at his disposal. By destroying temples and torturing and killing pagan resisters he succeeded in making every part of Norway at least nominally Christian. Expanding his efforts to the Norse settlements in the west the kings' sagas credit him with Christianizing the Faroes, Orkney, Shetland, Iceland and Greenland.
After Olaf's defeat at the Battle of Svolder in 1000 there was a partial relapse to paganism in Norway under the rule of the Jarls of Lade. In the following reign of Saint Olaf, 1015-1028, pagan remnants were stamped out and Christianity entrenched.
Following King Olaf I 's taking of Icelandic hostages, there were similar tension between the Christian and pagan factions in 10th century Iceland. Violent clashes were avoided by the decision of the Althing in AD 1000 to put the arbitration between them to Þorgeir Ljósvetningagoði, the leader of the pagan faction. He opted, after a day and a night of meditation, that the country should convert to Christianity as a whole, while pagan worship in private would continue to be tolerated.
The first known attempts to Christianize Sweden were made by Ansgar in 830, invited by the Swedish king Björn at Haugi. Setting up a church at Birka he met with little Swedish interest. A century later Unni, archbishop of Hamburg, made another unsuccessful attempt. In the 10th century English missionaries made inroads in Västergötland.
The historical tradition by Adam of Bremen mentions a pagan Temple at Uppsala in central Sweden. By 2001, the existence of this temple had not been confirmed by archaeological findings. Whether the remains of several large wooden constructions, found by excavations under the present church, are from a pagan temple or from an earlier church build in the same place, is disputed.
The adherents of the pagan temple drew a mutual agreement of toleration with Olof Skötkonung the first Christian king of Sweden who succeeded to the throne in the 990s. Christianity and paganism coexisted on an official level until the end of the 11th century.
Sources on Swedish history from this time are scant. What may be the one of the most violent occurrences between Christians and pagans was a conflict between Blot-Sweyn and Inge the Elder in the 1080s. This account survives in the Orkneyinga saga and in the last chapter of Hervarar saga where the saga successively moves from legendary history to historic Swedish events during the centuries before its compilation. The reigning king Inge decided to end the traditional pagan sacrifices at Uppsala which caused a public counter-reaction. Inge was forced into exile, and his brother-in-law Blot-Sweyn was elected king on condition that he allow the sacrifices to continue. After three years in exile, Inge returned secretly to Sweden in 1087, and having arrived at Old Uppsala, he surrounded the hall of Blot-Sweyn with his húskarls, and set the hall on fire, slaying the king as he escaped from the burning house. Hervarar saga reports that Inge completed the Christianization of the Swedes, but the Heimskringla suggests that Inge could not assume power directly, but had to dispose of yet another pagan king, Eric of Good Harvests. Inge's return to power is generally held to be the time of the destruction of the Temple at Uppsala, and in 1164, the Swedish archdiocese was established at the location.
The reason why the Swedish core provinces had coexistence between paganism and Christianity throughout the 11th century was because there was a general support for the transition towards the new religion. However, the old pagan rites were important and central for legal processes and when someone questioned ancient practices, many newly Christianized Swedes could react strongly in support of paganism for a while. Consequently, the vacillation between paganism and Christianity that are reported by the sagas and by Adam of Bremen were not very different from vacillations that appear in modern ideological shifts. It would have been impossible for King Inge the Elder to rule as a Christian king without strong support from his subjects, and a Norwegian invasion of Västergötland by Magnus Barefoot put Inge's relationship with his subjects to the test: he appears to have mustered most of the Swedish leidang, 3,600 men, and he ousted the Norwegian occupation force.
Although Sweden was officially Christianized by the 12th century, the Norwegian king Sigurd the Crusader undertook a crusade against Småland, the south-eastern part of the Swedish kingdom in the early 12th century, and officially it was in order to convert the locals.
On the northernmost runestone of the world standing on the island Frösön in central Jämtland, the Frösö Runestone, it is said that a man called Austmaðr christianized the region, probably in the period 1030-1050 when the runestone was risen. Little is known of Austmaðr, but he is believed to have been the lawspeaker of the regional thing Jamtamót.
Judging by archaeological finds, Christianity gained a foothold in Finland during the 11th century. It was strengthened with growing Swedish influence in the 12th century and the Finnish "crusade" of Birger Jarl in the 13th century.
In 1721, a new Danish colony was started in Greenland with the objective of converting the inhabitants to Christianity. Around the same time efforts were made in Norway and Sweden to convert the Sami (Lapps), who had remained pagan long after the conversion of their neighbours.