Two earls ruled in the Orkneys: Brusi and Thorfinn, half-brothers. Of the islands, two thirds were under Brusi, the elder; but besides his third Thorfinn had inherited Caithness and Sunderland in Scotland from his grandfather the Scot king. So Thorfinn lived on those lands, and Brusi guarded all the isles; but Thorfinn complained that the guard was