Charles II, Duke of Brunswick (1735-1806), was the son of Charles I, Duke of Brunswick-Wolfenbüttel, and Charlotte, daughter of Frederick William I, King of Prussia. In 1764 he married Augusta, Princess Royal, the eldest daughter of Frederick, Prince of Wales, and sister of George III. He succeeded as Duke of Brunswick in 1780. As a general in the Prussian army, he commanded the Allied armies of Austria and Prussia against the Napoleonic forces, but died of his wounds following the Battle of Jena in 1806. His daughter, Caroline, married George, Prince of Wales, and became Queen consort upon his succession as George IV.

This may be a version of the portrait in the Herzog Anton Ulrich-Museum, inv. 1332 (see also RCIN 451611). It is paired with the portrait of his wife, Augusta (RCIN 401267). The sitter appears head and shoulders; he wears a powdered hair, and a high collared blue coat with silver trim, decorated with a star on the breast; set against a cloudy blue sky.