I could say so much here but people are going to really hate me about this one.. (not that I care tho)
Christianity at that time was spreading like a plague. I believe many people converted because those were dark times indeed back then, if a party wants to, they can enter your village and kill you and your family and destroy the whole village.
The "brave men" and warriors killed eachother in battles/wars etc, they didn't return to their family which was waiting for them at home.
Sure, according to norse religion if you fight well then when you die you go to Valhalla, which sounds awesome, and I bet that's one of the reasons why vikings were so fierce, they believed in it, they KNEW it, it was a 100% fact to them so they maximized their abilities.
But there were people beside vikings, and even if they believed in that, a lot of them (especially the peasants, villagers etc) wanted to live their life fully. Not to die, not even for Valhalla and Valkyries, etc. But it was a sad life, imagine that one family dies of a plague, other killed by bandits, other killed by wild beasts, many other ones died just because a fat guy sitting on a throne decided the needs more money, etc.
Then come Christians with lust for power. I won't talk about Jesus, I won't blame him or something, maybe he did really want the best for his people. But, making a little note here before I proceed; if he's really God now, not just a random god, but the God whom the most people believe in, why doesn't he help them? I'm not talking about people randomly saying a miracle happened etc, i'm talking about things like, why doesn't he cures cancer completely?
There are 2 options (even 3):
1. He's not a god, he was a man, perhaps with talents, but he died like other people
2. He abandoned people and doesn't want to assist them because he knows they're scum. Only randomly you do see those "miracles" which might or might not be related to him.
3. He never existed at all. Not even as a man. History tells us bull****, religion tells us bull****, and crusaders and other zealots were thinking about something else (doesn't seem that realistic to me, tho).
Where was I now? Oh yes, then come Christians with lust for power, this is where I start blaming them, raging etc:
They want to conquer, but it's not easy to become king! You need a plan, a good plan, maybe good connections with people like at modern times, but you need to know your ****, because you either get killed and don't become anything, or a little group of idiots follow you and then a bigger group kills you and your puny kingdom.
So they come to the peasants, and ordinary warriors, like soldiers and maybe hired warriors/mercenaries I believe, and tell them:
But you have Jesus! Come and convert and you'll be alright, you will be saved, you will be pure, you'll go to heaven!
Translating this from lies to truth:
You have an imaginary friend, but he's above you, like the government. If you'll be a good dog he will pat you, and if you won't he will beat you.
But people don't have choice to think about questions like "is this lie or truth?". It's like I heard some guy, who said that somewhere in russia in the 90's, there was a woman and he asked her "who the hell are you?" and she told him "I am the mother of this world" and 200 people were following her and believing every word! It's amazing how people can be pathetic and naive when dark days are upon them.
People blindly follow, and those people blindly followed. The problem is not that people blindly followed, the problem is the AMOUNTS of people who blindly followed. And there were warriors too, there. But stuff like vikings was a big problem at first, when ppl just started to convert, vikings would come in and kill them.
Then the christians, seeing as they lose power (= lose chances to rise up high) say:
"Those pagans are scum, you need to hunt them down."
Even bigger problem is when they have facts to confirm their words:
"The village of X was raided by a pagan party! Come brothers and avenge them, come and kill the pagans!"
*raging note here: Fcking scum been spreading their lies and bull**** in a pagan land and expect no one to strike them back for it....
Then slowly the vikings and pagans were being hunted down, other pagans converted and you get a few kinds of people now:
People that converted a little later because they saw how their kind is being hunted down and saw no hope to continue believing in that religion as it will harm them.
And people that stood and fought til their deaths.
The so called Vikings were a minority, so parts of them lost hope and converted, the other were killed because they were protecting their land.
That's it.