 Prince William, Duke of Clarence and St Andrews, who later became King William IV of the United Kingdom, had at least ten children with his mistress Dorothea Jordan, all of whom took the surname FitzClarence.All of them were also granted by their father the rank of a marquess' younger sons or daughters.The Duke of Clarence's eldest surviving illegitimate child, George FitzClarence (1794–1842), was created Earl of Munster in 1831 and his male-line was continued until the death of The 7th Earl of Munster in 2000.