Until the commencement of the insurrection of 1745, Lord Kilmarnock enjoyed the possession of Dean Castle, a very ancient edifice, situated about half a mile north east of the town of Kilmarnock, in Ayrshire. "It is," says Grose in his Antiquities of Scotland, "at a small distance from the main road leading from Kilmarnock to Stewarton, and consists of a large vaulted square tower, which seems to have been built about the beginning of the fifteenth century: this is surrounded by a court and other buildings more modern."[329] Such is the description of Dean Castle before the year 1735; when, to add to Lord Kilmarnock's other necessities, it was partially destroyed by fire, leaving only a ruin which he was too much impoverished even to restore to its former habitable state. In the "great square tower," referred to by Grose, and of which a view is preserved in his work on Scotland, the Boyd family had dwelt in the days of their greatness, when one of their race was created Earl of Arran. In that tower had the Earl imprisoned his royal wife, the Lady Margaret, sister of James the Third, who was divorced from him, pleading, as some say, a prior contract with the Lord Hamilton, to whom she was afterwards united, taking to him the Isle of Arran as her dower. It does not appear that the Earl of Kilmarnock was originally in the confidence of the Jacobite party: and their designs were not only matured, but far in full operation before he took an open or active part in the Stuart cause. It happened, however, that when Charles Edward resided at Holyrood, the Countess of Kilmarnock was living in Edinburgh. Her beauty, and the gaiety of her manners, attracted the admiration of the young Prince, who bestowed no small portion of attention on the fascinating daughter of one of his father's adherents. Lady Kilmarnock was as much attached to pleasure as the young and beautiful usually are: she delighted in public diversions, and led the way to all parties of amusement. Her ambition, no less than her early prepossessions conspired, it is said, to make her a Jacobite; and she hoped, by the favour of Charles Edward, to obtain the restoration of her father's title. Her entreaties to the Earl of Kilmarnock to join the standard of the Prince were stimulated, therefore, by a double motive; and, indeed, to a generous and romantic mind, there required neither the inducements of ambition, nor of gratified vanity, to espouse that part which seemed most natural to the Scotch. After the battle of Preston Pans, Lady Kilmarnock's persuasions took effect: her husband presented himself to the young Chevalier, who received him with every mark of esteem and distinction, declared him a member of the privy council, raised him to the rank of a general, and appointed him colonel of his guards.[330] Another occurrence is, however, stated to have had a considerable influence in forming the Earl's decision.