Isabella Stanhope sat for Gainsborough at Bath early in 1769 shortly after her marriage to Viscount Molyneux. The artist had just been elected to the Royal Academy in London, and this work, sent soon afterwards to its first-ever exhibition, surely represents a deliberate effort to impress a London audience.
The figure has a brilliant poise and the play of light and shade on the satiny surface of her dress is a miracle of virtuoso painting.
Shortly afterwards her husband was made the 1st Earl of Sefton. This portrait hung at the Seftons' seat, Croxteth Hall near Liverpool, for two centuries until its acquisition by the Walker Art Gallery.