Dr John Wolcott was apprenticed to his uncle, a surgeon at Fowey, before attending Aberdeen University. In 1768, aged 29, he went with his patron Sir William Trelawny to Jamaica where he became Physician General in 1769 and was also ordained deacon. In 1773 he returned to England and began practising medicine in Truro. He was also a satirical poet writing under the name of Peter Pindar whose wit and sarcasm did not endear him to many of his townspeople. He was an amateur artist who had been a pupil under Richard Wilson. He became an early patron of Opie. This is one of about ten portraits that Opie painted of the doctor, who was also depicted together with Opie himself, as one of the assassins in his painting 'The Murder of James I', evidently as a personal joke between them.