 All that remained of his ambitions was Castle Coole itself, and that was really more a source of satisfaction to posterity than to himself, for he effectively handed over his various properties to his son and heir, Somerset, on his coming-of-age in 1795.Malcomson writes that by the time of Lord Belmore's death, the total debt affecting his estates stood at £133,000, of which about £70,000 was attributable to the building of Castle Coole, and that while the house was completed within his lifetime, it was not to be fully furnished until his son had inherited the estate.Lord Belmore was married firstly on 3 October 1771 to Lady Margaret Butler (23 January 1748 - Apr 1775), eldest daughter of Somerset Butler, 1st Earl of Carrick by his wife Lady Juliana Boyle, first daughter by his second wife of Henry Boyle, 1st Earl of Shannon, and had issue