I am unsure where this somewhat morbid fascination with the past history of marauding Norsemen going Viking comes from. After all they invaded the homesteads of foreign populations, looted, killed and enslaved until there was no one left. And then settled the lands for whatever it was worth.
But here we are and Viking Metal bands are legion these days, thriving in an ever increasing genre. And let’s face it: Metal with all its dark facettes is just perfect to describe yonder sea adventures and battles alike. RockmusicRaider already covered a score of Viking Metal bands, if you can call them that. Amongst which you will find the famous ones like Amon Amarth or the Canadians from SIG:AR:TYR.… Got hooked? Raid this some more...
Damn, I’m freezing! It is this cold, cold gale blowing down on us from the arctic North. Or is it the cold metal blasting out of my boom boxes? Luckily the winter is over soon and the frozen tundra and wind-blown plains between the Russian border and eternity will warm up. If not, these guys up in Finland will continue to find dark and cold tunes that will ice our bones and souls. And there is a bunch of them trying to drive us to tears with doomish and dark soundbites that flow towards us. 
See, it is indeed possible. You can write a complex metal tune without building brick walls so high that you won’t hear yourself anymore. And it can be done with a hike to the epic mountain top without firing up the mighty cheese machine too. 
What did I just read lately? Ah – yes – it went something like this – and I quote: “Always be yourself. But if you can be a Viking, always be a Viking.” 
The music really fits the theme. Even if they bemoan times long past and a mythology long out of fashion – the holy Roman church having taken over for some time now with some bloody vengeance too, by Loki. We are talking about Vikings and their doings, famous for invasions, violence and rape. This was a gore-laden time, but promising a lot of profit, if victorious. And they have been everywhere that could be reached on their little dragon boats. Perhaps the most famous actions being the invasions of the British isles back when the years were still counted in the hundreds and not the thousands.