About John Thornhill
John Thornhill was christened at Sr Giles in the Fields on 5 May 1700. He was the son of James (later Sir James) Thornhill and his wife Judith. John succeeded to his father's post as serjeant painter in July 1732. In 1735 John became one of the original 24 members of the Sublime Society of Beefsteaks and may by then have been working for the founder, John Rich, manager of Covent Garden Theatre. Thornhill was made free (by patrimony) of the Painter-Stainers Company in 1739. He was certainly employed as a scene painter at Covent Garden in 1746-47, when he received payments of £21 and £34 10s. He served as Master of the Painter-Stainers Company in 1748-49.
John Thornhill died in September 1757. As Paulson notes in his Hogarth, Thornhill had resigned the post of serjeant painter in favor of his brother-in-law William Hogarth in July 1757. On 12 August Thornhill made his will, naming, among others, Ebenezer Forrest and George Lambert the painter, both fellow members of the Beefsteaks. To each member of that Society Thornhill left mourning rings.
Thornhill's portrait was engraved by J. Whessell, after Hogarth, published as a plate to Ireland's Graphic Works in 1799 and incorrectly titled "Mr. Jas. Thornhill."