James O'Brien Irish politician (1695–1771) Parents Mary Villiers William O'Brien, 3rd Earl of Inchiquin Children Edward Dominic O'Brien Henrietta O'Brien Murrough O'Brien, 1st Marquess of Thomond Anne O'Brien Siblings William O'Brien, 4th Earl of Inchiquin Lady Henrietta O'Brien Lady Mary O'Brien Charles O'Brien Partners Mary Jephson