The Earldom of Orkney is the official status of the Orkney Islands, and was a Norse territory ruled by the earls (or jarls) of Orkney from the ninth century until 1472. It was founded during the Viking Age by Viking raiders and settlers from Scandinavia (see Scandinavian Scotland). In the ninth and tenth centuries it covered the Northern Isles (Norðreyjar) of Orkney and Shetland, as well as Caithness and Sutherland on the mainland. It was a dependent territory of the Kingdom of Norway until 1472, when it was absorbed into the Kingdom of Scotland. Originally, the title of Jarl or Earl of Orkney was heritable. The Northern Isles of Orkney and Shetland lie off the northernmost tip of Britain. By the Iron Age, they were part of the Pictish kingdom. From the late 8th century AD, the Picts were gradually dispossessed of the islands by the Norse from Scandinavia. The nature of this change is controversial, and theories range from peaceful integration to enslavement and genocide. Orkney and Shetland saw a significant influx of Norse settlers during the late 8th and early 9th centuries. Norse Vikings made the islands the headquarters of their pirate expeditions carried out against Norway and the coasts of mainland Scotland. In response, Norwegian king Harald Fairhair (Harald Hårfagre) is said to have annexed the Northern Isles in 875; although it is clear that this story, which appears in the Orkneyinga Saga, is based on the later voyages of Magnus Barelegs, and some scholars believe it to be apocryphal. Rognvald Eysteinsson received Orkney and Shetland from Harald as an earldom as reparation for the death of his son in battle in Scotland, and then passed the earldom on to his brother Sigurd the Mighty (ruled 875–892). However, Sigurd's line barely survived him and it was Torf-Einarr (ruled 895–910), Rognvald's son by a slave, who founded a dynasty that controlled the islands for centuries after his death. He was succeeded by his son Thorfinn Skull-splitter (910–963) and during this time the deposed Norwegian King Eric Bloodaxe often used Orkney as a raiding base before being killed in 954.