Europe had quite a few perfectly good religions in the fourth century already.
As a pure blooded Viking (Yep! As nearly as I can tell.) I have always wondered why my distant ancestors gave up on Thor, Odin, and the rest. I mean, they were pretty great! You don't see hot new Hollywood movies about Zarathustra. But starting around the fourth century, like dominos, kingdoms in Europe went Christian, one after another, plop, plop, plop! By 878, when Guthrum made a deal with Alfred in Britain (Oh ... and Christ too, by the way.) it was all over for the old Gods. Time to pack up the old broadaxe and truck it on back to Valhalla. (Sigh!!)
But why? What made Christianity so attractive?
It's not like it was a natural fit for the culture. Christ, after all, was this ragged politial malcontent who was part of a minor side channel dustup in a completely different part of the world. Christ himself really didn't last long and the main event in the movement he was part of took another 70 years to finally come to a head when Jerusalem was well and thoroughly trashed by the Romans. Nothing about the events that Christ was part of really had anything to do with Europe.
(Why Christianity instead of, say, "Paulianity" is another question. It's also fascinating, but not part of this topic.)
Thor, on the other hand, was the kind of guy that you could get down and enjoy a beer with.
The answer is really quite relevant to our times. The same sort of thing is happening today as you read these lines. The answer is Power -- How to get it and how to keep it.
The biggest difference between Odin and Jehovah is that Odin didn't care whether Guthrum or Alfred ruled in Wessex. Odin concerned himself with building a great wall around Valhalla and making sure that brave Viking men would be there to fight beside him at Ragnarok. But Jehovah did! In the Christian religion, kings are annointed by God. To rebel against the King is to rebel against God himself.
This was a handy concept that made the Jews (really a minor force by themselves) so tenacious in their defense of their little patch of desert and made the Moslems, six hundred years later, unstoppable until they ran up against people who had the same world view in Europe. It's one of the best examples of social evolution.
Judaism didn't really make the grade with this concept because it still had one minor flaw: "Jewish" was both a religion and a ethnicity and you can't convert someone's genes. But both Christians and Moslems believed that all you had to do is swear total allegience to their God and you were part of the club.
Think of becoming Christian (or Moslem) as being a lot like becoming part of the Borg. Resistance is futile!



