When Thorfinn’s maternal grandfather, King Malcolm, died, Kali Hundason[30] took the kingdom in Scotland. He attempted to exact tribute from Thorfinn for his dominions in the north of Scotland, and failing in this he sent his sister’s son, Moddan, into Caithness, giving him the title of Earl. Thorfinn was supported by the inhabitants, however, and after an unsuccessful attempt to establish himself in Caithness, Moddan returned to King Kali with the news that Thorfinn was plundering in Ross and Sutherland. King Kali embarked a considerable force in eleven ships at Beruvik (apparently Berriedale on the southern frontier of Caithness), and sent Moddan northwards by land with another division of his army, intending to enclose Thorfinn in the north-east corner of Caithness, and attack him from two sides at once. Thorfinn, however, was aware of the trap laid for him, and retired to the Islands. There Kali came up with him off Deerness, in Orkney, and a fierce battle took place, in which Kali was defeated. He fled southwards, and Thorfinn, following him, obliged him again to give battle at Baefiord, where he was again defeated, while Thorkel Fóstri fell upon Moddan at Thurso and slew him. Then, say the Sagas, Earl Thorfinn overran Scotland as far south as Fife, burning and slaying, and subduing the land wherever he went. By these conquests he became the most powerful of all the Earls of Orkney. Rögnvald Brusison was in Norway when he heard of his father’s death, and being odal-born to his father’s third of the Islands, and having received from King Magnus Olafson a grant of that third which King Olaf had declared forfeited to himself for Eyvind Urarhorn’s murder, he went west to the Orkneys, prepared to maintain his rights against the claims of Thorfinn, who had taken possession of the whole. An amicable arrangement was made between the kinsmen, and they joined their forces for viking forays upon the Hebrides, venturing even upon an extensive foray in England during the absence of Hardicanute in Denmark. After an eight years’ alliance, however, discord broke out between the kinsmen, and in a sea-fight in the Pentland Firth, off Rauda Biorg,[31] in Caithness, Rögnvald was defeated and fled, and Thorfinn reduced the whole of the Islands. Rögnvald went to Norway, and stayed some time with King Magnus. Then he came west to the Islands in a single ship, and surprising Thorfinn in a house on the Mainland of Orkney, he set fire to it. Thorfinn broke down part of the wall of the house and leapt out, carrying his wife Ingibiorg in his arms, and escaped through the smoke. Rögnvald, believing that Thorfinn had perished, took possession of the Islands. Thorfinn, who had got secretly over to his dominions in Caithness, returned shortly afterwards, and surprising Rögnvald in a house on Papa Stronsay, burnt the house and all who were in it, except Rögnvald, who sprang over the heads of the men who surrounded him, and got away in the darkness.