Portrait of John Fane, 10th Earl of Westmorland (1759-1841), as a boy, full-length, in a cream suit, holding a hat, with a terrier, by a plinth, in a park landscape

The sitter was the eldest son of John Fane, 9th Earl of Westmorland (1728-1774), and his wife, Augusta, daughter of Lord Montague Bertie. In 1782 he eloped with Sarah Anne (1764-1793), only child and heir of Robert Child of Osterley Park, Middlesex; they married against her father's wishes at Gretna Green on 20 May of that year. After his wife's early death in 1793, aged 29, he later married Jane (1779-1857), daughter of Richard Huck-Saunders in 1800. While at Cambridge, Westmorland formed a friendship with William Pitt the Younger, which was later resumed in parliament. In 1789 Westmorland was appointed Joint Postmaster General by Pitt, and sworn of the Privy Council. This came in the same year that he had been appointed Lord Lieutenant of Ireland by his friend, a post he held until 1794. From 1795 to 1798 he was Master of the Horse under Pitt and, in the latter year, was made Lord Privy Seal, a position he would hold under five prime Ministers for the next 35 years, apart from a brief period between 1806 and 1807 when Lord Grenville was in office.