Thomas Boyd, Earl of Arran's Coat of Arms

In 1467, Thomas, eldest son of Lord Robert Boyd was made Earl of Arran, and married Princess Mary, sister of King James III.  Thet lived in the newly built Palace at Dean Castle (then called Kilmarnock Castle), and their coat of arms can still be seen carved high up on the building, although the weather has almost worn them away.  Princess Mary had the Royal coat of arms - now commonly called 'The Lion Rampant' and her husband was allowed to 'impale' this with the Boyd coat of arms so that his new one was divided up the middle.  In Scottish heraldry the husband's coat of arms always comes on the left as you look at it.