By the tenth century, there was already a significant Christian presence in Norway. Some of the chieftains who ruled parts of the country were Christian, as were some of their followers. There was even a bishop in Norway from the 960s onward.
During this period, there were no kings who ruled over the entire territory that we now call “Norway.” A “king of Norway” in the tenth century meant a ruler who only controlled some large part of the country, and who had subdued the local chieftains who formerly held sway there.
The first “king of Norway” in that sense was Hákon Aðalsteinsfostri (“Hakon the Foster-son of Athalstein”), who ruled from about 935 to 960. Hakon had been baptized (as his name implies; to be someone’s “foster-son” in this context meant to have been baptized by that person), and established much of the initial ecclesiastical infrastructure in Norway. He doesn’t seem to have particularly bothered pagan worship along the way; he just set up the new system in its midst.
After a lapse during which the country was without a king, the next king in Norway was Olaf Tryggvason, whose turbulent, savage reign lasted a mere four years (995-999). Before becoming king, Olaf had been a leader of Viking raids in England. In the early 990s, the English King Ethelred offered Olaf a very large sum of money in return for a promise to never return to England to raid. Olaf accepted Ethelred’s offer. To seal the deal and to impart spiritual force to it, Ethelred baptized Olaf, making the Norwegian his foster-son – his spiritual kin.
In 995, Olaf sailed back to Norway loaded with English money to finance an attempt to become king. To do this, he first had to defeat and impose his will upon the chieftains who ruled the various parts of Norway.
Wealth wasn’t the only advantage Olaf had in this fight. Christianity was seen as a prestigious religion that made its devotees more socially and politically powerful through their ties with formidable European kings. This was especially true when there was a direct spiritual “lineage” traceable back to one of those kings, as there was in Olaf’s case. Christianity was therefore an impressive gift that Olaf could offer to those who agreed to fight on his side. His pagan competitors didn’t have anything comparable to offer.
According to the traditional biographies of Olaf, he used Christianity not only as a gift, but also as a weapon. He’s portrayed as an ardent Christianizer who made a habit of destroying pagan holy sites and converting his new subjects with a blade pressed against their throats.
To what extent do these legends reflect historical reality? Unfortunately, there’s ultimately no way to know for sure. One can readily argue both sides of the debate. On one hand, this portrayal of Olaf as a zealous missionizing king fits so snugly with the conventions of medieval hagiography that historians can’t help but view it with suspicion. On the other hand, however, Olaf’s motivation for forcible conversion would have been an utterly plausible one: by unifying Norway under Christianity, he would have been furthering his goal of unifying it under him as its Christian king. And by attempting to stamp out paganism in Norway, Olaf would have been eliminating his opponents’ ability to rally people around a sacred motivating factor in their opposition to him.If these stories are largely true, Olaf’s reign would be by far the most prominent exception to the otherwise mostly amicable and accommodating conversion of the Norse.
After another period in which Norway was without a king, Olaf Tryggvason’s distant relative Olaf Haraldsson assumed the throne and ruled from 1015 to 1028. Much like his predecessor, but to a lesser degree, Olaf Haraldsson is said to have destroyed pagan worship sites and imposed hardships on those who refused baptism.
Intriguingly, a runic inscription on a stone raised on the island of Kuli near Trondheim asserts that the stone was placed there at a time when “twelve winters had Christendom been in Norway.” Archaeologists have tentatively proposed, based on additional evidence from the site, that this date would have been 1022 – the middle of the reign of Olaf Haraldsson. What happened in 1022? We don’t know. Perhaps the king made the lands that he ruled formally Christian, or perhaps a local ruler accepted the faith in that year, or perhaps a large amount of the local populace was converted.