The blood eagle is a ritualized method of execution, detailed in late skaldic poetry. According to the two instances mentioned in the Sagas, the victims (in both cases members of royal families) were placed in a prone position, their ribs severed from the spine with a sharp tool, and their lungs pulled through the opening to create a pair of "wings". There is continuing debate about whether the ritual was a literary invention, a mistranslation of the original texts, or an authentic historical practice.
The blood-eagle ritual-killing rite appears in just two instances in Norse literature, plus oblique references some have interpreted as referring to the same ritual. The primary versions share certain commonalities: the victims are both noblemen (Halfdan Haaleg or "Long-leg" was a prince; Ælla of Northumbria a king) and both of the executions were in retaliation for the murder of a father.
Þar fundu þeir Hálfdan hálegg, ok lèt Einarr rísta örn á baki honum með sverði, ok skera rifin öll frá hrygginum ok draga þar út lúngun, ok gaf hann Óðni til sigrs sèr.
Einarr made them carve an eagle on his back with a sword, and cut the ribs all from the backbone, and draw the lungs there out, and gave him to Odin for the victory he had won.
Þá gékk Einarr jarl til Hálfdanar; hann reist örn á baki honum með þeima hætti, at hann lagði sverði á hol við hrygginn ok reist rifin öll ofan alt á lendar, dró þar út lungun; var þat bani Hálfdanar.
Afterwards, Earl Einarr went up to Halfdan and cut the "blood eagle" on his back, in this fashion that he thrust his sword into his chest by the backbone and severed all the ribs down to the loins, and then pulled out the lungs; and that was Halfdan's death.
In Þáttr af Ragnars sonum (the "Tale of Ragnar's sons"), Ivar the Boneless has captured king Ælla of Northumbria, who had killed Ivar's father Ragnar Loðbrók. The killing of Ælla, after a battle for control of York, is described thus:
They caused the bloody eagle to be carved on the back of Ælla, and they cut away all of the ribs from the spine, and then they ripped out his lungs.
The blood eagle is referred to by the 11th-century poet Sigvatr Þórðarson, who, some time between 1020 and 1038, wrote a skaldic verse named Knútsdrápa that recounts and establishes Ivar the Boneless as having killed Ælla and subsequently cutting his back.
Sighvatr's skaldic verse in Old Norse:
|Original||Literal translation||Suggested reordering|
Ok Ellu bak,
And Ella's back,
And Ívarr, the one
Skaldic verse, a common medium of Norse poets, was meant to be cryptic and allusive, and the idiomatic nature of Sighvatr's poem as a description of what has become known as the blood eagle is a matter of historical contention, particularly since in Norse imagery the eagle was strongly associated with blood and death.
Another possible oblique reference to the ritual appear in Norna-Gests þáttr. There are two stanzas of verse near the end of its section 6, "Sigurd Felled the Sons of Hunding", where a character describing previous events says:
Nú er blóðugr örn
There is debate about whether the blood eagle was historically practiced, or whether it was a literary device invented by the authors who transcribed the sagas. No contemporary accounts of the ritual exist, and the scant references in the sagas are several hundred years after the Christianization of Scandinavia.
Alfred Smyth supported the historicity of the ritual, stating that it is clearly human sacrifice to the Norse god Odin. He characterized St. Dunstan's description of the Ælla's killing as an "accurate account of a body subjected to the ritual of the blood eagle".
Roberta Frank reviewed the historical evidence for the ritual in her "Viking Atrocity and Skaldic Verse: The Rite of the Blood-Eagle", where she writes: "By the beginning of the nineteenth century, the various saga motifs--eagle sketch, rib division, lung surgery, and 'saline stimulant'--were combined in inventive sequences designed for maximum horror." She concludes that the authors of the sagas misunderstood alliterative kennings that alluded to leaving one's foes face down on the battlefield, their backs torn as carrion by scavenging birds. She compared the lurid details of the blood eagle to Christian martyrdom tracts, such as that relating the tortures of Saint Sebastian, shot so full of arrows that his ribs and internal organs were exposed. She suggests that these tales of martyrdom inspired further exaggeration of the misunderstood skaldic verses into a grandiose torture and death ritual with no actual historical basis. David Horspool in his book King Alfred: Burnt Cakes and Other Legends, while not committing to the historical veracity of the ritual, also saw parallels to martyrdom tracts. Frank's paper sparked a "lively debate".
Ronald Hutton's The Pagan Religions of the Ancient British Isles: Their Nature and Legacy states that "the hitherto notorious rite of the 'Blood Eagle,' the killing of a defeated warrior by pulling up his ribs and lungs through his back, has been shown to be almost certainly a Christian myth resulting from the misunderstanding of some older verse."