The Vikings were once the sworn enemies of Christendom. Within two centuries, however, most Vikings had adopted the religion they once despised, leaving pagan Norsedom in the ashes. This is remarkable transformation baffles modern scholars, and begs the question: how could Europe's most notorious raiders become such ardent believers? Was it for power, riches - or a genuine, heartfelt conversion?
Clash of Civilizations
In 793 A.D, a group of Norwegian Vikings attacked the illustrious Lindisfarne monastery. This was one of Western Europe's most important religious sites. The Vikings slaughtered the monks and plundered the gold. For Europeans, this was an unbelievable sacrilege, an omen of pure evil. For the Vikings, an all-too-easy loot.
In the following years, scores of raiding Vikings terrorised Britain's towns, villages, churches and monasteries, committing horrid atrocities. It soon spread to Frankia (France), the Holy Roman Empire (Germany), Spain and even Italy. Churchmen dubbed these Northern pirates as the Scourge of God.
In 850, the so-called Great Heathen Army invaded England (led by the Sons of Ragnar Lodbrok). The Vikings were now bound on territorial expansion, challenging the kingdoms of Christendom for political power. All the while, the brutality against Christians persisted.
But the world of Christendom fought back. By 890, the Anglo-Saxons had driven the Vikings back to the sea, and the Franks had found ways to halt their raids in Normandy. What had been unleashed, however, was a clash of civilisations. The raiding had initiated a struggle between Old Germanic Norsedom and Christianity.
Trade, Slaves and Hermits - the first, quiet signs
This was not the first time Western Europeans had encountered the Vikings. For centuries, Europeans had voyaged along the "North Way" trade route, stretching along the Norwegian coastline, in search of hides, ivory and other precious Arctic commodities.
Merchants who often traversed the trade routes would sometimes settle there, bringing their Christianity with them.
Vikings were also very avid slave traders. As the slave trade was frowned upon in Christian Europe, Scandinavia became a hot market to sell European slaves in. But these slaves were Christians. Based on medieval writings, scholars believe these slaves introduced Christianity to Norse families, and especially to the women. The women, in turn, influenced their husbands to listen to the testimonies of their servants.
The vast, barren landscapes also proved tempting for Christian hermits and monks seeking a life of seclusion. Some began to settle in deserted Scandinavian lands. Encounters with these strange, contemplative folk may also have advanced the Christian faith in Norse circles.
Ironically, the Vikings themselves often sailed out as pagans but returned to Scandinavia as Christians. Having bonded with Anglo-Saxons, Franks or Greeks, many admired the Christo-centric civilization. Vikings who enlisted in Christian armies also typically had to get baptised beforehand. All this led to the conversion of lots of Viking warriors, who then brought crosses and Bibles back home to Scandinavia.
In the late-800s, it is believed that the Norwegian coastline already had enclaves of Christian communities. In Denmark, Christianity was even more prevalent. King Harald Klak of Jutland converted already in 825. In 829, King Bjorn the Tall in Sweden not only converted - but requested missionaries from Hamburg to come to Sweden and preach Christianity. In come St. Ansgar - the "Apostle of the North".
St. Ansgar preached in Sweden and, reportedly, conducted mass baptisms before returning to Hamburg. As Archbishop, Ansgar organised missions across Denmark and Sweden, establishing good relations with Norse monarchs to permit their entry.
However, in the 840s the Great Heathen Army was raiding at will in England, and the clash between Norsedom and Christendom was at its peak. Norse communities began showing stiffer resistance to the new faith. In 845, Norse Danes raided Hamburg, destroying the holy sites and burning all the books.
Despite this setback, St. Ansgar continued his missionary work out of Bremen and personally voyaging into Sweden by himself in order to accomplish his tasks.
The Kings Convert
In 958, the King of all Denmark, Harald Bluetooth, converted to Christianity and was baptised in a public ceremony. All his court followed suit. This cemented Christianity in Denmark, and Danish society adapted to the new faith.
Harald Bluetooth's baptism was a major turning point. A united Denmark was now ruled by a Christian King. But this did not mean the political wars with the rest of Europe had ended. Far from it. The Danes would continue invading England, but now there would, at least in official terms, be granted more respect to Christian holy sites.
Norway also had a Christian King at this time, Haakon the Good, but his faith was not as warmly embraced. After he had erected a series of churches along the coast, bands of Norse pagans began burning them down. When King Haakon confronted the pagans, he was humiliated and forced to sacrifice to the old gods to avoid an open revolt. It was an embarrassing episode that demonstrated the superior power Norwegian farmers had over their kings. From that moment on, Christianity in Norway became a very politicized arena.
The Importance of St. Olaf
In 1015, Olaf Haraldsson seized the throne. Once an atrocious villain who had plundered churches and cities, Olaf was now baptised and had an ardent desire to revamp all of Norway and make it like the other feudal kingdoms of Europe. He, therefore, made the monarchy stronger, founded the Church of Norway and introduced a series of new laws rooted in Christian ethics .
He inevitably met resistance, but surprisingly not on religious grounds. Almost all of Norway was already Christian, thanks to the effects earlier described. Instead, Olaf's enemies simply resisted his feudalist politics. Many defected to King Cnut of Denmark, forcing Olaf to flee his kingdom. In 1030, he returned but was killed at the battle of Stiklestad.
Olaf Haraldsson's life seems underwhelming - but his death was quite the opposite. Posthumously, scores of people began calling Olaf a holy man. Even his enemies - his very killers - confessed it. As the clergy dug up his deceased body, they found it uncorrupted, an indisputable mark of holiness.
It seems paradoxical - even futile - to proclaim such a violent man as a Saint. But Olaf's Sainthood is not about him, but about his people. He was a Viking who once committed horrific acts of sacrilege. After his conversion, he was torn by the wedge between his Norse lifestyle and the ideals of Christianity and fell many times. But in the last year of his life, when he was exiled and lost it all, the sagas reveal that he finally rid himself of his ego and fully repented. He still had to pay the price - ride into battle and face death - but he did so willingly, fully submitted to Gods will.
Thus, his very life and death became symbolic of the conversion of Scandinavia. It resonated with all the other thousands of Vikings whose crimes convinced them they would never attain God's mercy. St. Olaf became the proof that even a man with an atrocious track record could, through repentance and by God's grace, be embraced by God as one of His finest.
As words of his Sainthood spread across Scandinavia, Christianity gained a sense of respect and admiration. The miracle of incorruptibility was uncontested, making even Norsemen acknowledge the power of St. Olaf's faith. Folk from Britannia to Russia came to Norway to venerate his relics, and so-called "St. Olaf's churches" were erected all over Northern Europe. A complete paradigm shift had occurred over all of Scandinavia - Christianity was never contested again.
What drove the conversion of Scandinavia?
So, what forces drove this unprecedented transformation?
It is undeniable that there was a politico-cultural element at play. In contrast to Scandinavia, the world of Christendom was spoiled with wealth and advanced cultures . For Vikings, these wealthy towns were perfect prey for rape and plunder. But it soon morphed into a sense of respect. Many mercenaries, traders, sailors - even Kings - possibly converted to become a part of this promising civilization.
The early life of St. Olaf is a clear testament to this. Not only did he convert, but he implemented the same European political model in his own country, trying to help the Kingdom of Norway produce similar results as Frankia, England, etc.
Of course, the Norse political elite sometimes used baptism to secure political alliances (Harald Klak of Jylland is a good example of this). This explanation is a favourite of modern scholars, presenting the conversions as being solely for political intentions. However, it does not capture the full picture. Scandinavians kept warring with Christian kingdoms despite having converted, showing a surprising lack of faith-based "alliances" after baptism. Then there are the baptised Kings who spent their lives spreading the religion in their homeland - why bother if the conversion was merely a ceremonial gimmick? Perhaps spreading Christianity was done to justify feudalism, which granted Kings more authority - but what about St. Olaf's killers, who were also Christians, yet anti-feudalist? They simply resisted his political ideology, not his religion, suggesting that conversion to Christianity was not a necessity for feudalism to be implemented.
Thus, we see elements of sincerity hidden between the lines. This is nothing new. It was always there. The Viking Christians who returned home did so knowing that they would be religious minorities in a hostile, political environment. This is a curious move if the intention was merely to enjoy the perks of Christendom.
The conversion rate was accelerated by the quiet entry of Christian slaves, missionaries and traders, initiating an underground, social turn to Christianity. It simply awaited the attention of Scandinavias Kings and Earls, and in the 900s, it happened. King Harald Bluetooth of Denmark, King Haakon the Good of Norway, King Olaf Skottkonung of Sweden - Christianity gained the hearts of the Kings.
It began as a Clash of Civilizations but as Scandinavians migrated to Christian lands, and intermingled with Christians, a rich cultural and religious exchange began. Norsedom failed to spread anywhere in Christian Europe. Instead, Christianity spread successfully in Norse Scandinavia.
Thus, we see a gradual process.
The lower classes adopted the faith but kept it private.
As the clash with Christian Kingdoms intensified in the outside world, tolerance to the growing religion soured, causing a more tense political climate.
Then, the upper and ruling classes began to convert, reverting the political pressure back at the pagan Odin-worshippers.
As the Kingdoms were transformed into feudal ones, the last pagans were viewed more as stubborn rebels than fellow countrymen. Facing this, paganism gradually died out.
Finally, if there was any paganism lingering on by 1030, the Sainthood of Olaf stamped it out.
What began with an attack on Lindisfarne Monastery in 793, therefore, had culminated in the complete extinction of the Norse pagan religion, and the triumph of Christianity in Scandinavia.
 The Christian Law of St. Olaf and Bishop Grimkell stated that slaves had to be freed every 7th year, work was disallowed on Sundays, abortion was illegal, and blood-feuding was outlawed, among many social and religious laws.
 Many aspects of Viking society were advanced in their own right, especially in areas pertaining to power devolution, law and trade (read my article: How the Vikings made the West for more information). However, the overall splendour of the Christian kingdoms was still unmatched.