the vikings were really remarkably successful, weren't they?
maybe, a little too successful, if you see what i mean.
there's a developing understanding that the viking attack on europe was a reaction to the advance of christianization, and that the historical sources (written almost entirely by the church...) just kind of "forgot" to record that fact. but, you have to understand that the scale of devastation that the spread of christianity brought to northern europe was many times worse than anything the vikings produced. charlemagne literally slaughtered entire castes of people. again: the records are poor, but it could have been in the hundreds of thousands, in an era where the population was much, much lower than today.
if you're standing in denmark, and you're watching what's happening directly to your south, it's hard to imagine that you wouldn't want to respond. and, the culture to the north was shared, so the danes were capable of a call to arms.
again: this much is developing scholarship. i'm not making this up. this is not novel.
what i'm willing to put forward is the idea that they may have even been interpreted as liberators by a european population that was struggling against colonization by the roman/christian church. the vikings very specifically targeted the christians, pretty much everywhere they went, which is why the texts, written by monks, demonized them so terribly. and, sure - they burnt down a fair number of churches. the traditional explanation was that they were pillaging, although, as mentioned, this is evolving to the idea that the vikings were carrying out what they saw as acts of self-defense.
but, there are these reports of continuing odinism deep in england and france well into the enlightenment. the old religion really went underground. as far as anybody knows, it eventually disappeared; at the least, if they're still out there, it would be useful for them to inform the views of these "neo-pagans" that have as much in common with the indigenous european religions as harry potter - the old religion is lost to history. but, we know damned well that it survived way, way longer than history officially records.
and, even if the western europe of the time was pious to the church, what allegiance ought it have had to these frankish warlords, that ruled through tyranny and heavy taxation, as they put in motion the beginnings of feudalism? at least the vikings believed in democracy.
it's just hard to read the history critically without coming to the conclusion that there were substantive parts of these populations that helped the invasions. the timelines are incredible: paris conquered as quickly as it took to sail up the seine. how does that happen without local support?
but, the idea is taboo.
i would request that more serious historians look into this more carefully.