On ivory, in a red leather case, 5cm.
Isabella Poyntz was the daughter and heiress of William Stephen Poyntz of Cowdray. She married Brownlow, 2nd Marquess of Exeter (1795-1867) in 1824.
The miniature was painted the following year, perhaps to celebrate the birth of a son and heir, William Alleyne, Lord Burghley and future 3rd Marquess, (1825-1895).
Anthony Stewart initially trained in Edinburgh with a landscape artist, before turning to miniature painting, which he pursued in both Edinburgh and London.
He usually specialised in painting children and painted many miniatures of the young Princess Victoria throughout her childhood.