Robert Stewart, 1st Marquess of Londonderry

Robert Stewart, 1st Marquess of Londonderry PC (Ire) (1739–1821), was a County Down landowner, Irish Volunteer, and member of the parliament who, exceptionally for an Ulster Scot and Presbyterian, rose within the ranks of Ireland's "Anglican Ascendancy." His success was fuelled by wealth acquired through judicious marriages, and by the advancing political career of his son, Viscount Castlereagh. In 1798 he gained notoriety for refusing to intercede on behalf of James Porter, his local Presbyterian minister, executed outside the Stewart demesne as a rebel.