"But," he said, "just at first I must ask for sacrifices from you. This castle is strong, but it must be made much stronger, and must be capable of standing a continued siege in case temporary reverses should enable the English to endeavour to retake it for their friend, Sir Allan Kerr. My vassals at Glen Cairn have promised an aid far beyond that which I can command, and I trust that you also will extend your time of feudal service, and promise you a relaxation in future years equivalent to the time you may now give."

The demand was readily assented to, for the tenants of Aberfilly were no less delighted than those of Glen Cairn to escape from the rule of the Kerrs. Archie, accompanied by Sir John Grahame, now made an inspection of the walls of his new hold. It stood just where the counties of Linlithgow and Edinburgh join that of Lanark. It was built on an island on a tributary of the Clyde. The stream was but a small one, and the island had been artificially made, so that the stream formed a moat on either side of it, the castle occupying a knoll of ground which rose somewhat abruptly from the surrounding country. The moat was but twelve feet wide, and Archie and Sir John decided that this should be widened to fifty feet and deepened to ten, and that a dam should be built just below the castle to keep back the stream and fill the moat. The walls should everywhere be raised ten feet, several strong additional flanking towers added, and a work built beyond the moat to guard the head of the drawbridge. With such additions Aberfilly would be able to stand a long siege by any force which might assail it.