The sitter was the eldest son of George Rose (1744-1818) and Theodora, daughter of John Duer of Fulham and Antigua. He was MP for Southampton from 1794 to 1818 and Christchurch from 1818 to 1832, and again from 1837 to 1844. He was Envoy Extraordinary to Munich and Berlin and to the US. When he retired from political life he wrote several works on the Old Testament. During his time in politics he published A Letter on the Means and Importance of Converting the Slaves in the West Indies to Christianity. A proprietor in the West Indies by inheritance, Rose believed that the spread of Christianity among the slave population was beneficial to society as a whole. He presented a petition for the abolition of slavery in 1830.
A full-length drawing of the sitter by Richard Cosway, signed and dated 1787, was sold Christie's, London, 17 June 1975, lot 54. A portrait miniature of the sitter's wife, Jane Frances Rose (d. 1851), Attributed to Richard Cosway, was sold Bamfords, 2-5 December 2014, lot 2013. It was sold together with the present lot when they came up for sale at Sotheby's in 1945. She was the daughter of Thomas Duncan (d. 1779) from Duncan Park, Helmsley.