Thorfinn The Mighty

Thorfinn Sigurdsson (1009?–c. 1064?), called Thorfinn the Mighty, was an 11th-century Earl of Orkney. One of five brothers (with Brusi, Sumarlidi, Einar and Hvelp), sons of Earl Sigurd Hlodvirsson by his marriage to the daughter of Malcolm II of Scotland. Thorfinn was the youngest of the five known sons of Earl Sigurd Hlodvirsson, but the only son of Sigurd's marriage to a daughter of Máel Coluim mac Cináeda. His elder half-brothers Einar, Brusi and Sumarlidi survived to adulthood, while a brother called Hundi ("the Dog") or 'Hvelp ("the Whelp") died in Norway, a hostage at the court of King Olaf Trygvasson. Thorfinn married Ingibiorg Finnsdottir, daughter of Finn Arnesson, Jarl of Halland.

The Heimskringla of Icelandic historian Snorri Sturluson, and the anonymous compiler of the Orkneyinga Saga, wrote that Thorfinn was the most powerful of all the earls of Orkney. He is said to have been earl for seventy-five years and ruler of nine earldoms in Scotland, of the Hebrides, and of part of Ireland. A sizable part of the account in the Orkneyinga Saga concerns his wars with a "King of Scots" named Karl Hundason whose identity is very uncertain.