This is a portrait of Ann Miles whose sister Elizabeth married John Thirtle in 1812. Ann Miles married John Sell Cotman in 1809. Two portraits of Ann Miles are known, one in Leeds City Art Gallery, the other recorded in the collection of A.M. Cotman (see S. Kitson, The Life of John Sell Cotman, London, 1937, illustrated opp. p. 171). A group of five portraits of members of the Miles family is in Norwich Castle Museum, and a group portrait of John Sell Cotman, Mrs Edmund Miles and Anne Miles in their farmhouse, Felbrigg, Norfolk was sold in these Rooms, 16 November 2006, lot 106.
The present watercolour is a rare portrait watercolour by Thirtle who is known primarily for his landscapes.