When did the era when Richard Cosway was a leading English portrait painter end?
Richard Cosway: Richard Cosway {'1': ", '2': ", '3': 'RA', '4': "} (5 November 1742 – 4 July 1821) was a leading English portrait painter of the Regency era, noted for his miniatures. Regency era:  The Regency era ended in 1837 when Queen Victoria succeeded William IV.
1837