"Einar had his ribs cut from the spine with a sword and the lungs pulled out through the slits in his back. He dedicated the victim to Odin as a victory offering."
Also known as the Burning Wings, the blood eagle is one of the most horrible methods of execution known.
Performed by sons on the murderers of their fathers, it was a Viking tradition in which a victim is tied between two posts whilst the shape of an eagle was cut into the back of them and the skin removed. The ribs were then cracked off with the aid of a hammer or mallet (or in the case above, a sword) and pulled apart, exposing the lungs. The lungs were then pulled out through the back of the victim and nailed to the posts on either side of the victim, above his head, giving the appearance of wings. Death came from shock and asphyxiation.
Variations of the punishment include the lungs being pulled out through small slits in the back, and the skin of the back being wholly stripped off and spread out to create larger wings before the lungs were removed.
To get an idea of what this bloody ritual might have looked like, think of the scene in “The Silence of the Lambs” film when Hannibal is discovered to be missing. The police officers enter the room and see Officer Boyle suspended above the cell in a blood eagle. It is not clear whether this was performed posthumously.