Robert Stewart (1769-1822), Viscount Castlereagh, later s... 1817
Robert Stewart, 1st Marquess of Londonderry, MP (1739–182... 1784
Robert Stewart (1774/5-1799) of Castle Stewart and St For... 1794
Robert Stewart, 2nd Viscount Castlereagh, later 2nd Marqu... 1800
Frederick William Robert Stewart, 4th Marquess of Londond... 1856
Robert Stewart, 1st Marquess of Londonderry (1739–1821)
