Antoinette (1779-1824) was the second daughter of Francis, Duke of Saxe-Coburg-Saalfeld. In 1798, she married Alexander, Duke of Württemberg, a younger brother of Frederick I, King of Württemberg. She was the aunt of both Queen Victoria and Prince Albert. This portrait was probably painted about 1798, the year of her marriage, aged 19. Miniature portraits of her sisters, Sophia and Juliana, are also in the Royal Collection (RCIN 420805 and  RCIN 420588).

Jean-Augustin Ritt (1765-1799) was a German artist. His father, Johann Ritt, from Prague, was kapellmeister of the imperial orchestra in St Petersburg, where Jean-Augustin was born. In 1781, Jean-Augustin went to Antwerp to study painting where he remained until 1786. He moved to Paris, where he studied with André François Vincent, the miniaturist and etcher. He left Paris in 1792 and returned to St Petersburg where he remained as imperial court painter until his death. His diary, which he kept from 1781 to1799, lists 700 paintings.

The miniature is signed on the lower right: Ritt, and the backing paper is inscribed in pencil: Grossfürstin (Grand duchess).