James Scott, 1st Duke of Monmouth, recognized by some as James II of England, (1826). James, Duke of Monmouth (1649-1685), Pretender to throne of Scotland and England. Monmouth, the illegitimate son of Charles II and Lucy Walter launched a rebellion in 1685. Claiming to be Charles' rightful heir, he attempted to overthrow the Roman Catholic King James II. His revolt ended in defeat at the Battle of Sedgmoor, Somerset, on 6 July 1685 and Monmouth was subsequently beheaded on Tower Hill.