@Anna Kristin Petursdottir: You obviously did not understand Mike Stangels request correctly. He points out that Snorre Sturlasson (b.1179) couldnt prsonally have known Skule "Kongsfostre" (b. 1052) - which is obvious because these two individuals lived at different times. He further points out that Snorre could have known Skule Bårdson as they both lived during the same period of time.. He did not say that Skule Kongsfostre på Rein and Skule Bårdsson could be the same person, as you seem to imply.
You seem to believe that your "paper trail pedigree" confirms that this listing on Geni is more or less correct, but most modern historians would find that it is most certainly uncertain. Among others, Mason (2004: 103-104) finds it unlikely that Ketil and Skuli were sons of Judith of Flanders, Earl Tostig's wife since 1051. Mason argues that Ketil and Skuli were Scandinavian names, whereas one would expect the boys to receive names from the House of Flanders if Ketil and Skuli actually were Judith's biological offspring. Moreover, Mason points out, if they were Judith's offspring, it is more likely that they would have sought refuge in Flanders after the 1066 Battle of Stamford Bridge.
Mason (2004: 103-104) writes that Tostig 'may well have had a previous partner, or partners, while still in his teens, before his marriage' (cf. more danico). The Norse sagas are ambiguous as to Skuli and Ketil. Some places, they are presented as brothers. Other places, only Skuli is presented as a son of Earl Tostig, while Ketil is presented as hailing 'from the north of Hålogaland' (norðan af Hálogalandi).
Elaborating this idea, Martinsen (2024: 13, 45) has suggested that Ketil and Skuli were maternal half-brothers. Their mother first had Skuli by a native aristocrat of Trøndelag in Norway, before marrying Tostig and giving birth to Ketil. Assuming that Ketil was her second son, he would normally be named after his maternal grandfather, according to contemporary naming customs. Thus assuming that Ketil's mother was NN Ketilsdotter, she was most likely a descendant of Ketil Trout the Older of Ramsta (cf. Ketils saga hœngs).
Supporting the alleged link to Trøndelag, Martinsen (2024: 45) emphasises that the name Skúli was so to say endogenous to Norway (later also introduced in Iceland by Norwegian settlers), writing:
Whilst Ketil (Kjetil) was a pan-Scandinavian name, we cannot ignore that the name Skúli (Skule) prevailed in Norway and Iceland. It might not have been a coincidence that King Olaf III assigned Skuli to Rein in Trøndelag and Ketil to Torgar, not far away from Ketil Trout’s Ramsta. We sense that Skuli’s father may have been from Rein and that Skuli’s and Ketil’s mother was from Ramsta. This must, however, be subject to future research.
The thought that Tostig had a spouse from Norway is not implausible, considering that Tostig himself had a Danish mother, Martinsen (2024: 45) argues. Tostig's mother was Gytha Thorkelsdottir, whose extended in-law family included King Canute of England, Denmark, and Norway. In other words, Tostig belonged to a transnational royal family network that also had a migratory residence pattern.
In his youth and (or) adolescence, Tostig must have visited Trondheim, the then-capital of Norway, as part of King Canute's entourage or as a guest at the viceregal court. We can imagine that having met NN Ketilsdotter there, Tostig took her and her son Skuli with him to England. It is unknown whether Ketil himself was born in Norway or England.
Ketil was born before c. 1051, when Earl Tostig married Judith of Flanders, but after c. 1042, when Earl Tostig, himself born c. 1026, reached the age of 16 years. Presupposing that Earl Tostig at least was 20 years old when he fathered Ketil, his son was born between 1046 and 1051.
