Mary Capell was born 13 October 1722 to William Capell, 3rd Earl of Essex (1698-1743) and Jane Hyde (c1699-1724) and died April 1782 of unspecified causes. She married John Forbes (1714-1796) 25 August 1758 .
|Offspring of John Forbes and Mary Capell (1722-1782)|
|Maria Eleanor Forbes (1761-1844)||January 1761||18 March 1844 Clarendon House, North Audley Street, Mayfair, London, England, United Kingdom||John Charles Villiers, 3rd Earl of Clarendon (1757-1838)|
|Katherine Elizabeth Forbes (1761-1851)||January 1761||23 October 1851 Grosvenor Square, Mayfair, London, England, United Kingdom||William Wellesley-Pole, 3rd Earl of Mornington (1763-1845)|