2. Malcolm's second daughter, Donada, he married to Finnleac or Finlay Mac Ruari, Maormor of North Moray, and a chief of the northern Picts, and they had a son, Macbeth, born about 1005, who succeeded Duncan I on his death in 1040 as King of Scotland, but left no issue.[3]
3. Malcolm's third daughter, said to have been called Plantula, he gave, about 1007, as his second wife to Sigurd Hlodverson, who, as we have seen, was killed in 1014 at the decisive battle of Clontarf, his wife having died probably before that event; and their only child was a son, born about 1008 and created Earl of Caithness and Sutherland, who became the great Earl and Jarl Thorfinn.
The three marriages were intended to secure to Malcolm the south, the middle, and the north of Pictland through the fathers of Duncan, Macbeth, and Thorfinn respectively; and we may note that from Thorfinn are descended all subsequent Jarls and Earls of Orkney and Shetland and Caithness of the so-called Norse line.
Duncan I, Macbeth, and Thorfinn Sigurd's son were thus first cousins, and, in spite of the fiction of Holinshed, Boece, and William Shakespeare, they were all about the same age, being born within seven years of each other; and none of them lived to old age.
By the victory of Carham in 1018 Malcolm II secured for ever the line of the Tweed as Scotland's southern frontier; and this success in the south, one of the most important events in Scottish history, left him free to extend his kingdom and sovereignty towards the north, his object being to unite into one realm the whole mainland at least of Scotland. To accomplish this, he would have to bring under the supremacy of the Scottish crown in addition to the Picts of Atholl, whom the Scots had absorbed, the Gallgaels of Argyll, the Picts of Moray and of Ross within and beyond the Grampians, and those of the province of Cat, with the Norsemen there as well. He could thus ultimately hope to oust Somarled, Brusi and Einar, Jarl Sigurd's sons by his first wife, and their overlords, the Norse kings, from Orkney and Shetland, and to add those islands to his dominions. Meantime, Somarled, Brusi and Einar took no share in Cat. Thorfinn had Cat, all for himself, as a fief of the Scottish king.
Although the history of the time of Thorfinn Sigurdson, the first Scottish Earl of Caithness and Sutherland,[4] would have been of great interest to inhabitants of those counties, the Orkneyinga Saga contains but little information about his doings in them, because he bent all his efforts towards extending his dominion over the islands which formed his father Sigurd's jarldom, his policy, in his youth at least, being directed to this object by his grandfather, Malcolm II. Indeed during the life of that king, Thorfinn appears to have established himself at Duncansby in Caithness, on the shore of the 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 Thorkel Fostri, whom Einar plotted to kill. Einar next seized Eyvind Urarhorn, a Norse subject of distinction, who had caused his complete defeat in Ulfreksfirth in Ireland, but was sheltering from a storm in Orkney, and killed him, to the great anger of the Norse king.
Grasping at once the opportunity thus created, Thorfinn determined to turn it to his own advantage. He sent Thorkel to King Olaf in Norway to seek protection for himself against Einar, and Thorkel came back bearing an invitation to Thorfinn to visit the Norwegian court, from which the jarl returned as much in favour with the king as Einar was in disgrace. Brusi then tried to reconcile Thorfinn and Einar, and Thorkel was to be included in the settlement. Thorkel, however, after inviting Einar to a feast in his hall at Sandvik in Deerness, a promontory south-east of Kirkwall, discovered a plot by Einar to attack him by three several ambushes as they left the house. In a striking scene, the Saga tells how Thorkel, wounded, and Halvard, an Icelander, dispatched Einar at the hearth of the hall; how Einar's followers did not interfere; and how Thorkel fled to King Olaf in Norway, who was much gratified by the death of Einar, the slayer of his own friend Eyvind Urarhorn.[7]
On Einar's death, Brusi tried to get two-thirds of the isles, but Thorfinn now claimed a half share, and King Olaf, in spite of a visit by Thorfinn to him in Norway, ultimately awarded Brusi two-thirds, Thorfinn having the rest. Brusi, however, being unable to defend the isles from pirates, about the year 1028 gave up one of his trithings to Thorfinn on his undertaking the defence of the isles,[8] for which a powerful fleet would be essential, and Brusi died in 1031.