Interpretations
Hunter (2000) states that Ketill was "in charge of an extensive island realm and, as a result, sufficiently prestigious to contemplate the making of agreements and alliances with other princelings". However, Woolf (2007) suggests that the story of his failing to pay tax to Harald "looks very much like a story created in later days to legitimise Norwegian claims to sovereignty in the region" and some scholars believe that this entire story of Harald's expedition is apocryphal and based on the later voyages of Magnus Barelegs. Although Norse military activity in Ireland in the 9th century is well documented in Irish sources, they contain no record at all of Harald Fairhair's voyage to the west.
Furthermore, Harald is assumed to have annexed the Northern Isles (comprising Orkney and Shetland) in 875 or later. If Ketill's suzerainty post-dates this time, it is hard to see how Thorstein the Red, an adult grandson of his, could have been in active in the 870s and 880s. It is therefore likely that Ketill's floruit in the Hebrides was at a period that pre-dates Harald's victory at Hafrsfjord.
Read more about this topic: Ketill Flatnose