Danloux, who trained at the Académie des Beaux-Arts under N-B Lepicie, spent five years in Rome (1775-80) before establishing his reputation in Lyon, then Paris, as a painter of genre scenes and portraits (notably the small, full-length portrait of the Baron de Besenval in his study that was recently acquired by the National Gallery, London). Forced into exile by the Revolution in 1791, Danloux spent the next decade in London working as a highly successful portrait painter. He represented one of the most up-to-date examples of a fashionable French artist that English painters could encounter in London, and upon his return to Paris in 1800 he was instrumental in communicating the English style - especially that of George Romney, to whom he was particularly close - to his French colleagues.
H.R.H. Augustus Frederick, Duke of Brunswick-Luneburg, Duke of Sussex from 1802, Grand Master of the Freemasons of England from 1813, and President of the Royal Society from 1830 to 1838, was born 27 January 1773 at Buckingham House. He was married, against the Royal Marriage Act, in Rome on 4 April 1793, to Augusta, second daughter of John Murray, fourth Earl of Dunmore, and a woman considerably his senior. A second marriage ceremony followed at St. George's, Hanover Square, 5 December 1793, and this portrait was commissioned shortly thereafter, perhaps in honor of the marriage. It is probably the picture exhibited by Danloux at the Royal Academy in 1795.
In 1802, after the birth of their second child, the couple separated. Following the death of Augusta in 1830, the Duke married Cecilia Letitia, daughter of the second Earl of Arran and widow of Sir George Stubbins, a solicitor. Augustus Frederick died at Kensington Palace 21 April 1843; his second wife lived another thirty years.