Duke of Richelieu
Duke of Richelieu was a title in the French nobility. It was created on 26 November 1629 for Armand Jean Cardinal du Plessis, (Cardinal Richelieu) who, as a Roman Catholic clergyman, had no issue to pass it down to. It instead passed to his great-nephew, Armand Jean de Vignerot, grandson of his elder sister Françoise (1577–1615), who had married René de Vignerot, Seigneur de Pontcourlay († 1625).