The Sackville Children 1796 John Hoppner British The children of the third Duke of Dorset were painted at Knole, the Sackville family seat. They are (left to right): Lady Mary Sackville (1792-1864); the Duke's only son, Lord Middlesex (1793-1815), later fourth Duke of Dorset; and Lady Elizabeth Sackville (1795-1870). The picture was exhibited in 1797 under the title "Portraits of a nobleman's children." The pose of the boy derives from a famous portrait of Henry VIII by Hans Holbein.. The Sackville Children. John Hoppner (British, London 1758-1810 London). 1796. Oil on canvas. Paintings