Note: from Kevin Walters:

See bk&q chart 28, NB19, pp 378, 391-5, 398, 415, 425, 446, 447, 488, 754

p 447 Thorfinn II shared part of the earldom of Orkney from 1018, most of it from 1028 and all of it from c1030 except for 1038-46, when he shared it with Ragnald II. Thorfinn's inheritance is complicated. He was the son of Sigurd II after his second marriage to Donada, the daughter of Malcolm II of Scotland, and thus half-brother to Macbeth. When his father died at Clontarf in 1014, Thorfinn was only six or seven and was left in the care of the Scottish king. Mlcolm confirmed Thorfinn as earl of Caithness, and installed him at Duncansby with a body of advisers and guardians. The leading official was Thorkel, known as the Fosterer. Malcolm clearly saw this as an opportunity to gain control over Caithness and possibly Orkney itself. It also gave him a powerful ally over the mormaers of Moray. He thus supported Thorfinn as he grew into an intelligent but precicious young man, ambitious for power and wealth. Even at the age of eleven, possibly less, he became embroiled in a squabble over inheritance with his half-brothers, following the death of Somerled, who had left his territory to Einar, who was every bit as ambitious as Thorfinn. Thorfinn, no doubt urged on by Malcolm, disputed Einar's share. Einar refused to budge, on the basis that Thorfinn already had Caithness, which was not part of the arrangement. Two years of negotiation ensued, mediated by the third brother, Brusi. Eventually, in 1018, Brusi bequeathed Einar his share of the land on the basis that Einar shared a third with Thorfinn. Einard did so, but refused to pay Thorfinn his share of the revenues. To settle the dispute Thorfinn travelled to the court of Olaf, king of Norway, in the summer of 1020. Olaf supported Thorfinn and gave both him and Thorkel a longship each. They returned to Caithness and prepared to embattle Einar until Brusi negotiated a peace. Einar visited Thorkel at Sandwick, where he was promptly murdered. Thorkel was forgiven for this crime by King Olaf (who had no love for Einar) but he used it as an opportunity to claim a share of the Orkneys himself, so that by 1021, Brusi, Olaf and Thorfinn each administered a third. Thorfinn negotiated to administer Olaf's third as a fief of the king, which was agreed, but Brusi also earned the king's respect and was allowed the greater share of the earldom. From 1021 to 1028 therefore, Brusi was the senior earl and administrator of Orkney, whilst Thorfinn retained one-third of the earldom, plus his own earldom in Caithness. Brusi eventually handed over the majority of the earldom to Thorfinn in 1028, and all of it in 1030. It was retaining his hold on Caithness that occupied much of the time from then on. The lands had long been under threat from Findlaech, Malcolm and Gillecomgain, the mormaers of Moray. It is recorded that Thorfinn was in battle against them for much of his early adult life, though this changed when his half-brother Macbeth succeeded to the stewardship. By then Thorfinn's main adversary was the man the sages call Karl Hundisson, who was probably the Scottish king Duncan I, Thorfinn's cousin. Duncan/Hundisson invaded Caithness in 1040 with a view to conquest but was defeated by Thorfinn twice, resulting in Duncan's death. Thorfinn followed up this victory by not only reclaiming Caithness but Sutherland, Moray and Ross, so that he now dominated all of northern Scotland. In 1038 Thorfinn was forced to share a third of the earldom with his nephew, Ragnald, the son of Brusi, who had been confirmed as earl by the king of Norway. Thorfinn tolerated Ragnald at first, in fact they seemed to work well together, and the two of them reconquered the Western Isles, which had been lost to the earldom since Clontarf. Thorfinn also exacted retribution upon Ireland for its support of Hundisson and in 1042 raided as far south as England, probably using the Isle of Man as his base. Thorfinn had no serious ambitions on England. It was as much a show of strength, but it confirmed his authority. He and Ragnald now ruled over half of Scotland, including all of the surrounding islands. Unfortunately by 1045 the relationship between the two suffered when Thorfinn demanded Ragnald pay over the revenues from his third to help support the Norse earl, Kalf Arnesson, who had fled from Norway to seek refuge in the Orkneys. Thorfinn had married Kalf's niece, Ingiobiorg, some years earlier. Ragnald refused and after a year of arguing, Ragnald went to Norway, received the support of King Magnus, and returned to the Orkneys with a fighting force. He defeated Thorfinn at first, but then Kalf Arnesson brought his soldiers into the picture and he and Thorfinn drove Ragnald back to Norway. Ragnald was reinforced by King Magnus, returned and caught Thorfinn by surprise, burning down his house. Thorfinn escaped to Caithness, but in his turn, came back and burned Ragnald's house. Ragnald was killed while escaping. Thorfinn reconciled himself with King Magnus and from then till his death was the sole earl of Orkney. He now underwent a conversion and, in 1048, went on a tour through the courts of Europe, culminating in a visit to the pope, who forgave him for his past sins. It is not stated that Thorfinn was baptized into the Christian faith, but after 1048 he was a professed Christian and, on his return to Orkney, he established an episcopal church beside his royal household at Birsay, with its first bishop Thorolf. With the help of Thorolf, Thorfinn completely reorganized the administrative and legal structure of his earldom. Surprisingly the exact date of his death, which followed a long illness, is not known. It is unlikely to be as late as 1065, as often recorded, because his widow Ingibiorg married Malcolm III of Scotland and bore three children before 1069. He probably died between 1057 and 1060. Although his territories were always subject to the king of Scotland (on the mainland) and the king of Norway (Orkney and the Western Isles), Thorfinn seems to have governed with almost total autonomy, certainly towards the end of his life, and was ahead of his Scandinavian contemporaries in establishing a bishopric on his lands. Despite his early petulance and ambition, he became a wise and dedicated ruler, recognized throughout Europe, though today he is one of the forgotten great rulers of Britain. After his death his lands were shared between his two sons, Paul and Erlend II.