Question: When did the era when Richard Cosway was a leading English portrait painter end?
Sentence (from "Regency era"): The period from 1795 to 1837, which includes the latter part of the reign of George III and the reigns of his sons George IV and William IV, is often regarded as the Regency era, characterised by distinctive trends in British architecture, literature, fashions, politics, and culture.
Relevant evidence: No