Well this came out of left field for me – thanks for the link, Kaiju! Second look at the Darkness?
Not only is this a manly-ish track with a cool animation, but it mentions Edmund the Martyr – a Christian saint. My interest piqued, I did a little Googling.
The song centers on actual historical figures, it appears. The details of the story vary, as it seems the vikings laid waste to his kingdom and left little to tell of this Anglo-Saxon king. Common accounts of his reign, based on legend and tradition perhaps passed on from his time, say that he ascended to the throne of East Anglia at the age of 14 or 15 and ruled as a just and wise king. He was notably pious and brave.
Around 870 AD, his kingdom was invaded by the Great Heathen Army, a huge force of Danish vikings led by Ivar the Boneless, who has apparently been portrayed in a number of modern media (including Crusader Kings II). As noted in the song, Ivar was the son of the legendary Norse king Ragnar. King Edmund was able to repel the initial barbarian force, but was eventually overwhelmed. He was reportedly captured and, after refusing to renounce Christ, tortured and killed. At one point he was considered the patron saint of England, and was widely venerated.
Nice little bit of Christian history/lore to learn from a random hard rock song.