The sitter became a lieutenant colonel in 1758 and served under the Marquess of Granby as commissary general to the Hessian troops serving as part of the allied forces in Germany under Prince Ferdinand of Brunswick. He was described by Lord Clive as ‘one of the best, if not the best office in the King’s service’. He spent most of his military career abroad, including Gibraltar where he was named lieutenant governor in 1768 and became a major general in 1772. Later, when acting governor, he began work on the ‘king’s bastion’, a fortress with a capacity of 800 men and twenty-six cannons and mortars and which still stands today. He was awarded the Order of the Bath in 1785 but had to wait until 1788 for his investiture. By 1791 he was governor of Gibraltar and he died there at the age of 84.
Another miniature by Smart depicting the same sitter in uniform, signed and dated 1784, was sold Christie’s, London, 26 June 1979, lot 57, as the Property of William Feilden, Bt. A further, in plain clothes, is recorded in D. Foskett, op. cit., p. 63.