[1] Early in that year, he procured the marriage of his eldest son, Thomas, (created Earl of Arran for that occasion) with Mary Stewart, Princess of Scotland, elder sister of James III, which aroused the jealousy of the other nobles[2] and made his eventual downfall inevitable, since King James III regarded the marriage of his sister as an unforgivable insult.
Lord Boyd obtained the cession of the Orkney Islands to Scotland, on 8 September 1468, from Christian I, King of Norway, for whose daughter Margaret, he negotiated a marriage with James III.
[1] While absent for that purpose he and his son Thomas (the Earl of Arran) and his brother (and coadjutor) Sir Alexander Boyd, were attainted for high treason, whereby his peerage became forfeited.
[2] James III's biographer sums Boyd up as an unscrupulous political gambler and an inveterate optimist.
[1] He was the son and heir of Sir Thomas Boyd of Kilmarnock (died 9 July 1439).