Viking Metal is among the more peculiar subgenres within heavy metal. Unlike so many other styles, this one is not defined by any one particular sound, which makes it pretty broad, necessitating a journey through 20 Albums That Define Viking Metal's Evolution.

The credit for inventing Viking Metal is largely placed on the head of late Bathory visionary Quorthon, who had also propelled black metal's advancement during the late '80s. However, the source of Viking themes in metal pre-dates Bathory's historical lyrical leanings and it's Manowar who implemented tales of this bygone warrior era, which dovetailed beautifully with Norse mythology.

Of course, Led Zeppelin may have been the true source of inspiration for all this battle-ready heavy metal thanks to the release of "The Immigrant Song" in 1970 and it's iconic opening lines, "We come from the land of the ice and snow / From the midnight sun, where the hot springs flow / The hammer of the gods / We'll drive our ships to new lands / To fight the horde, and sing and cry / Valhalla, I am coming!"

While mostly rooted in extreme metal (black and death metal more specifically), these are far from prerequisites for playing what can be dubbed Viking Metal. Really, all you have to do is play any form of music recognizable under the great banner that is the whole of heavy metal and write about Vikings. Simple enough, right?

So don your armor, make sure your sword is sharp, raise your horn and board the longships — the battle awaits!

20 Albums That Define Viking Metal's Evolution