The Boyds of Kilmarnock

King James III became King of Scotland in 1460.
Scotland was first governed by James's mother, Mary of Gueldres (died 1463) and James Kennedy, Bishop of St. Andrews (died 1465).
Then a group of nobles headed by the Boyds of Kilmarnock governed Scotland. The Boyds seized James III in 1466.
In 1469 James overthrew the Boyds. He began to govern for himself.
Suppose James III does not overthrow the Boyds. How long do they remain in power?

On the death of King James II, Robert Boyd, 1st Lord Boyd was appointed as one of the regents to the young James III.
Boyd's younger brother was appointed as the military tutor to the new King.

Lord Boyd conspired with his brother, Sir Alexander Boyd, and obtained possession of King James III in 1466.
By Act of Parliament Robert Boyd was made sole Governor of the Realm; and Great Chamberlain for life, and Lord Justice General in 1467.