Pentland Firth, and to have occupied himself in endeavouring to induce
his three surviving half-brothers, Somarled, Brusi, and Einar, to part
with as large a share as possible of Orkney and Shetland, and cede
it to himself. In this he had much assistance from King Malcolm.
Thorfinn, whose mother probably died in his infancy if we are to
credit his father's matrimonial stipulations as regards an Irish wife
in 1014, succeeded to the earldom and lands in that year, as a boy of
about six years of age, and was early in coming to his full growth,
the "tallest and strongest of men; his hair was black, his features
sharp, his brows scowling, and, as soon as he grew up, it was easy to
see that he was forward and grasping." From the description given in
the Saga at Chapter 22, he was no more a Norseman in appearance than
he was by blood. He was, in fact, by race and descent, almost a pure
Gael, and at Malcolm's court must have spoken only Gaelic.

Of his three half-brothers, Somarled and Brusi were not unwilling to
give Thorfinn a share of the Orkney jarldom. For they were meek men,
especially Brusi; and, when Somarled died, though Einar wanted two
shares for himself, and fought to retain them, he only wearied out
his followers and alienated them by his cruelty. They, therefore, went
over to Thorfinn in Caithness. More important still, Thorkel
Amundson, "the properest young man in Orkney," did likewise, and was
thenceforward known as Thorkel Fostri, foster-father to Thorfinn, whom
he aided at every crisis of his career.

When Thorfinn grew up, he claimed a third share of Orkney, and,
not getting it, "called out a force from Caithness" where he mostly
lived.[5] Brusi and Einar then pooled their share of the islands,
Einar having the control of both; and Thorfinn got his trithing,[6]
managing it by his men, who collected his scatt and tolls under