Who married Lady Mary Capell?

Admiral of the Fleet John Forbes (17 July 1714 – 10 March 1796) was a Royal Navy officer and politician. After taking part in an expedition to Lisbon to support the Portuguese in the face of a Spanish threat, he saw action as captain of the third-rate HMS Norfolk at the Battle of Toulon during the War of the Austrian Succession. He was one of the few captains who really bore down on the enemy.

Forbes went on to serve as a Lord Commissioner of the Admiralty under successive governments. In that role, he was convinced of the illegality of the sentence of death on Vice-Admiral John Byng and refused to sign Byng's death warrant. He also served as Member of Parliament for St Johnstown and then as Member of Parliament for Mullingar in the Parliament of Ireland.