In the National Archives of Scotland (GD112/1/8) are Letters dated 20 November 1454 by George (Lauder), Bishop of Argyll, reciting apostolic Letters of Pope Nicholas of 5 April 1454, for the marriage of Colin Campbell, Knt., of Glenurquha, and Jonet Stewart, daughter of John Stewart, Lord of Lorne, who are within the forbidden degrees of consanguinity.

It has been suggested that the terms of the dispensation deliberately understated the degrees of consanguinity between the couple, and the marriage was therefore illegal. In June 1473, Richard persuaded his mother-in-law to leave sanctuary and come to live under his protection at Middleham.

He is said to have had consanguinity with the Saxon kings.