Lady Isabella Bennet (1667-1723), only daughter and sole heir of Henry Bennet, 1st Earl of Arlington, was pre-contracted in marriage to Henry Fitzroy, Earl of Euston, later 1st Duke of Grafton, K.G. (1683-1690), the second illegitimate son of King Charles II, by Barbara Villiers, Countess of Castlemaine, in 1672, when five years old. The marriage took place on 6 November 1679 and was witnessed by the diarist John Evelyn who commented that 'the sweetest, hopefulest, most beautiful child, & most virtuous too , was sacrific'd to a boy that had been rudely bred' although he added that he was 'exceedingly handsome, by far surpassing any of the King's other naturall issue' (Evelyn, 4. 184-5). The Duchess of Grafton is shown in this portrait with their eldest son Charles, later 2nd Duke of Grafton, K.G. (1683-1757). What is likely to be the prototype of this portrait type, which is signed and dated 1692, is recorded in the collection of the Duke of Grafton (for which see J. Douglas Stewart, Sir Godfrey Kneller and the English Baroque Portrait, Oxford , 1983, p. 107, no. 315).