When Christianity spread across Scandinavia during the Viking Age, it changed many Norse cultural norms. The following are three of the most notable changes that took place as a result of their Christianization.
Prior to converting to Christianity, Norse culture valued good grooming habits. We know this from several sources, including both Christian and Muslim texts, as well as archeological finds of combs, washbowls, and saunas. Christianity, however, viewed Norse grooming habits as signs of vanity. In Christendom, it was required of some people, especially clerics, to never bathe. In fact, monks actually thought the dirtier they were, the holier they were because they were rejecting vanity. As Christianity spread across Scandinavia, the Scandinavian people joined the rest of Christendom in their smelliness. Read more about Norse grooming.
2. Religious Tolerance.
History has shown time and again that polytheistic religions tend to be more tolerant of other faiths. Norse paganism was no different. Their tolerance for other belief systems may have contributed to their Christianization as they may not have seen Christianity as a threat. Christ would have just been another deity among the many in the world to them. Christianity tends to be intolerant of other religions as all the Abrahamic religions are. And once Christianized, the once tolerant Norse people became as intolerant of other religions as the rest of Christendom. Read about the Norse culture of learning.
3. Separation of Church and State.
Prior to Christianization, Norse culture did not separate religion from politics. Religious festivals and observances were the duty of the Jarl or Chieftain of the community to organize and carry out, sometimes aided by other religious figures (with the temple at Uppsala as the main exception). Christianity put an end to this tradition and passed the duty of religious observance to clerics and the Church rather than to the leader of the community. This change took power away from local leaders and gave more power to the church. The separation of church and state was originally devised to consolidate power within the church because most governments were unreliable and changed leadership frequently. Not until much later in the medieval period would more powerful, stable monarchs begin to take a more active role in the church, eventually becoming figureheads associated with divinity.