The Kilmarnock Line

Following on from April, William Boyd, 4th Earl of Kilmarnock (Grand Master Mason 174243) was executed on Tower Hill and thus forfeited all his titles to the Crown. He was married into the family of theEarl of Erroll with children:

1. Hon William Boyd, styled Lord Boyd

2. Hon James Boyd later Hay, styled Lord Boyd, later 15th Earl of Erroll (see below)

3. Capt Hon Charles Boyd

4. Capt Hon William Boyd

On 17 Jun 1831 his great-grandson,William George [Hay], 18th Earl of Erroll, was created Baron Kilmarnock, of Kilmarnock in the County of Ayr.

Despite the family connection, it did not stop the Craft electing James Hay, Lord Boyd(afterwards 15th Earl of Erroll) as Grand Master Mason in 1751—52. In 1751, however, although theEarldomwas abolished, James was permitted to inherit the Kilmarnock estates. These included Dean Castle, the former family seat which had been gutted by a fire in 1735. Trying to recoup some of his father's debts (which he had also inherited), James sold the ruined castle to the13th Earl of Glencairn.

On 19 August 1758, he succeeded his maternal great-aunt, Mary Hay, 14th Countess of Errollas the15th Earl of Erroll,simultaneously changing his surname from Boyd to Hay, as he and his descendants were henceforth known.