"Civilization" is ill-defined anyway. What's certain is that long before they embraced Christianity in a form other European Christians would recognize as such, they admired Europe. Europe had great buildings, castles, cathedrals, palaces, walled cities, places of learning, markets, unlike anything in Scandinavia at the time. They wanted those things. And they could only get so far as pirates and slavers.

Interesting that you see it as a higher ethics to be OK with only enslaving non christians, because I really did not mean anything like that, as I do not see it as a higher ethic.

And like the other commenter pointed out, civilization is ill defined. I was mainly using it here from the christian point of view, where pagans are not civilized by definition. Not that the norse had not a complex society themself.

"I do not think its entirely true to say Christians were "free to plunder and enslave non-Christians""

Well, I am not a historian, but was there any war against pagans, that was stopped by the church or individual priests?

(talking about medieval times, modern christianity is a bit different, but the old tradition seems to get a revival in certain circles)

The most I know of, is individual priests who for example criticize the acts of the conquistadores. But crusades to "spread" christianity were rather pushed as a sure way to get into heaven as far as I know.

"The crusades were not financially remunerative - the crusaders mostly lost money."

That is probably why they stopped doing it. Before christianity they had all the coasts of europe to blunder. After their kings turned christians who made treaties with the mainland christian empires - that was not possible anymore and raiding, even under the disguise of crusade, much harder and therefore less attractive (apart from that I did not claim that my explanation is the explanation, just a contributing factor)

Conveniently the hammer is deceptively similar to the cross in general shape.

Thanks, I will give it a try then.