Thorfinn Torf-Einarsson

It is likely that Dungad was a member of a pre-Norse era ruling family and that the marriage brought Groa's descendants within the Celtic derbfine and helped to legitimise their ambitions on the north mainland of Scotland.

[6] In the later days of Thorfinn's rule, the sons of Eric Bloodaxe fled Norway and returned to Orkney where they "committed great excesses".

Ragnhild had her husband Arnfinn killed at Murkle in Caithness and married his brother Havard "Harvest-happy"[9] who then ruled as earl for a time.

There is clearly a chronological problem with Earl Hlodvir, whose son Sigurd was killed at Clontarf in 1014, marrying the daughter of a king who died more than 120 years before that.

[14] Thomson (2008) concludes that there is "no real reason to trust the details of this bloodthirsty story" about Thorfinn's children, and speculates about the saga writer's intentions.

[9] He identifies these family feuds as being the main theme of the Orkneyinga saga, culminating in the martyrdom of St Magnus c.1115, and that the writer is emphasising the doom of "kin-slaying".

The connection with Erik Bloodaxe may also have been made to illustrate the continuing influence of the Norwegian ruling families in Orcadian affairs, which lessened in the late 10th century when Scandinavian expeditions tended to be directed towards England "by-passing Orkney and allowing the earls greater scope for independent action".

[9] Although he never became de facto earl, Skuli Thorfinsson's relationship with the Scots offers some insight into the politics of the north of Scotland in the late tenth century.

Crawford (1987) suggests that "if the late ninth-century conquest of northern Scotland by Thorstein the Red and Sigurd the Mighty had indeed led to permanent colonies in Caithness and along the coastal areas of Sutherland, then the late tenth century struggle may have been a result of aggression from the Scottish side in an attempt to regain control of the northernmost province of the Scottish mainland".