While the killing of Hálfdan by the Orkney islanders is recorded independently in the "Historia Norvegiæ", the manner of his death is unspecified. The blood eagle sacrifice may be a misunderstanding or an invention of the sagawriters as it does not feature directly in the earlier skaldic verses, which instead indicate that Hálfdan was killed by a volley of spears. The verses do mention the eagle as a carrion bird, and this may have influenced the saga writers to introduce the blood eagle element. The sagas then relate that Harald sought vengeance for his son's ignoble death, and set out on campaign against Einarr, but was unable to dislodge him. Eventually, Harald agreed to end the fight in exchange for a fine of 60 gold marks levied on Einarr and the allodial owners of the islands. Einarr offered to pay the whole fine if the allodial landowners passed their lands to him, to which they agreed. Einarr's assumption of control over the islands appears well-attested and was considered by later commentators to be the moment at which the Earls of Orkney came to own the entire island group in fee to the King of Norway. Others have interpreted the payment of 60 gold marks as wergild or blood money.