The blood eagle was a method of ritually executing a chosen member as 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 has been continuing debate about whether the rite was a literary invention, a mistranslation of the original texts, or an authentic historical practice. Accounts 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 practice. 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. Einarr and Halfdan There are two sources that purport to describe Torf-Einarr's ritual execution of Harald Fairhair's son, Halfdan Long-Leg, in the late 9th century. Both were written several centuries after the events they depict, and exist in various versions known to have influenced each other. In the Orkneyinga saga, the blood eagle is described as a sacrifice to Odin. Snorri Sturluson's Heimskringla contains an account of the same event described in Orkneyinga saga, with Einarr actually performing the deed himself: Ragnar Lodbrok's sons and King Ælla of Northumbria 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: 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: {| |- style="text-align:left;" !width=25%| Original !width=35%| Literal translation !width=30%| Suggested reordering |- | style="padding-right:1em" | | style="padding-right:1em" |And Ella's back, at, had, the one who dwelt, Ívarr, with eagle, York, cut. |And Ívarr, the one who dwelt at York, had Ella's back cut with [an] eagle. |} 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