the age of eighty; and his death wrecked his policy. For Duncan,
his grandson, the Karl Hundason of the Saga, on his accession to
the Scottish throne claimed tribute from his cousin Thorfinn for
Caithness. Payment was at once refused, and six years of strife,
interrupted by Duncan's unfortunate raids south of the Tweed, ended by
his creating Mumtan or Moddan, his own sister's son, Earl of Caithness
instead of Thorfinn. With a force collected in Sudrland, which thus
appears to have been on the Scottish side, Moddan tried to make good
his title, but Thorfinn raised an army in Caithness, and Thorkel
collected another for him in Orkney, and the Scots retired before
superior numbers. "Then Earl Thorfinn fared after them, and laid under
him Sudrland and Ross and harried far and wide over Scotland; thence
he turned back to Caithness," and "sate at Duncansby, and had there
five long-ships ... and just enough force to man them well."[9]

After his retirement in Caithness, Moddan went to Duncan at North
Berwick, and Duncan sent him back with another force by land to
Caithness, proceeding thither himself by sea with eleven ships. Duncan
caught Thorfinn and his five ships off the Mull of Deerness in the
Mainland of Orkney, where, after a stiff hand-to-hand fight, the Scots
fleet was defeated and chased southwards by Thorfinn to Moray, which
he ravaged.[10]

Finding that Moddan and his army were in Thurso, Thorfinn sent Thorkel
Fostri thither secretly with part of his forces, and he set fire to
the house in which Moddan was, and killed him there as he tried to
escape. Thorkel next raised levies in Caithness, Sutherland, and Ross,
joined forces with Thorfinn in Moray, and harried the land, whereupon
Duncan collected an army from the south of Scotland and Cantire and
Ireland, and attacked his enemies in the north.