James Crofts, later James Scott, 1st Duke of Monmouth an 1st Duke of Buccleuch (April 9, 1649 – July 15, 1685), was an English nobleman who was executed in 1685 after making an unsuccessful attempt to claim the British throne, the Monmouth Rebellion. He was born in Rotterdam in the Netherlands, the illegitimate son of Charles II and his mistress, Lucy Walter, who had followed him into continental exile after the execution of Charles II's father, King Charles I.