This portrait is a late work by the artist. The pattern is derived from Lely's portrait of Henry Howard, 6th Duke of Norfolk, which is signed and dated 1677 (R.B. Beckett, Lely, London, 1951, p.55, no. 384). A portrait of Lord Cornwallis, of the same pattern, is at Audley End. The sitter in this portrait has traditionally been identified as the Duke of Monmouth but appears more likely to be another of King Charles II's illegitimate children.