Henry FitzRoy was born in 1663 the natural son of Charles II and Barbara Villiers, Countess of Castlemaine and later Duchess of Cleveland, one of the great beauties of the Restoration era.

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Charles II arranged a preliminary marriage in 1672 when Henry was a boy of nine, to a five year old heiress, Isabella, the daughter of the eminent statesman Henry Benet, Earl of Arlington, who owned Euston Park in Suffolk. The confirmatory marriage took place in 1679 when Henry was sixteen and Isabella twelve. The lands in Grafton had been given to Charles's Queen, Catherine of Braganza, in 1665, and  as she had not produced any heirs by 1673, a reversionary grant was made 'in consideration of natural love and affection to his natural son'. Henry was thus created Duke of Grafton in 1675. The Duke was appointed Colonel of the First Foot Guards, Vice-Admiral of England and Knight of the Garter. In 1683 he suppressed the Corsairs in Tunis. In 1690 the 27 year old Duke took command of the ship that had been named after him accompanying the Earl of Marlborough to Ireland. He was shot down whilst leading his troops ashore at the siege of Cork. He died eleven days later from his wounds. On his death he was succeeded by his only son, Charles.