Morkinskinna [276] states that Skúli was a son of Tostig, and mentions Ketill in the same passage without giving any relationship. In a passage describing the same events, Heimskringla [660] states that Skúli and Ketill were brothers of noble English blood, but does not state their parentage. (Some published versions of Heimskringla based on later manuscripts make the brothers sons of Tostig, but this is not in Hollander's translation, based on the earliest manuscripts.) Skúli was evidently an adult at the time of the Battle of Stamford Bridge (1066), and it has also been pointed out [Cleve & Hlawitschka (1982), 27] that the Norwegian names Skúli and Ketill are unknown among Tostig's and Judith's families, so it seems unlikely that they were children of Judith, and it would be extremely difficult to identify them with the children of Judith mentioned above who were still infants in 1065. If these sons have been correctly attributed to Tostig (and that itself is not certain), then they would have been much more likely to have been born by a Norwegian wife or mistress prior to Tostig's marriage to Judith
