Colonel Sir Horace Beauchamp Seymour was the son of Admiral Lord Hugh Seymour and Lady Anne Horatia Waldegrave (see lots 24 & 25). He first married Elizabeth Malet Palk in 1818 and had three children, including Lt.-Col. Charles Francis Seymour (see lot 282) and Adelaide, Countess Spencer (1825-1877), second wife of Frederick, 4th Earl Spencer. He later married Frances Selina Isabella, Lady Clinton, daughter of William Stephen Poyntz and the Hon. Mary Browne and sister of Frederick, 4th Earl Spencer's first wife Elizabeth Poyntz (1799-1851). He served in the cavalry at the Battle of Waterloo, and eventually attained the rank of Colonel.
The present miniature derives from a signed and dated portrait on paper by Jean-Baptiste Isabey of 1820, once in the collection of Adelaide Horatia Spencer (1825-1877), second wife of Frederick, 4th Earl Spencer, and daughter of the present sitter. The portrait was exhibited London, South Kensington Museum, Special Exhibition of Portrait Miniatures, 1865, no. 2129 (lent by The Dowager Countess Spencer and as 'one of the few miniatures painted by the artist during his short residence in England'). It was later exhibited in Malmaison, Musée national des Châteaux de Malmaison et Bois-Préau, Jean-Baptiste Isabey, portraitiste de l'Europe (1767-1855), 2005-2006, no. 172, p. 151, illustrated in colour p. 87 (private collection).