Fans of the hit History television show Vikings will remember that a ritual was performed on Jarl Borg (played by Thorbjorn Harr) called the "Blood Eagle." In what was perhaps the most captivating part of the show (albeit the bloodiest), the execution of the traitor received rave reviews from critics. Meanwhile, the show's stars gave mixed reviews from Borg's wife passing out, to Aslaug gasping in horror, to Lagertha watching with pride. So, what is the blood eagle? How important is it? Did it even really exist?

There's some question as to the validity of the blood eagle. On one hand, it is depicted on some Old Norse paintings, enscriptions, and stone reliefs. There's also a very notable depiction in The Story of Norna Gest, which is translated below:

"Now the blood eagle
With a broad sword
The killer of Sigmund
Carved on the back.
Fewer were more valiant
As the troops dispersed
A chief of people
Who made the raven glad."

This suggests that this was a method of execution reserved especially for killers and traitors.

But on the other hand, there was certainly some reason for Christians to exaggerate the depictions of the Blood Eagle to serve their own needs (How much less brutal was crucifixion, really?). What better way to implant your own religion into the minds of others than to say that the old religion is "violent" and "brutal?"

Whatever the case, it was depicted on Vikings as a semi-religious ritual. In summary: Jarl Borg's back was opened with a knife. Then his ribs were separated from his back. Next, he was disemboweled. He was then left to die of exposure. He cried out in pain as it all was going on -- and good luck finding someone who wouldn't -- which denied him entry into Valhalla. Most gruesome of all, his blood spilled out onto the skull of his first wife (Borg had an ongoing relationship with her throughout the series), who died during their wedding. Trust me, you'll have to watch for yourself to fully understand.

Check out the video recap of episode 7 below. (WARNING: GRAPHIC!)