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 clergyman, had no issue to pass it down to. It instead passed to his great-nephew, Armand Jean de Vignerot,[1] grandson of his elder sister Françoise (1577–1615), who had married René de Vignerot, Seigneur de Pontcourlay († 1625).

Armand Jean de Vignerot added the cardinal's surname of du Plessis to his own, took the cardinal's coat of arms and received the titles of Duke of Richelieu and Peer of France by letters patent in 1657.

Two new reversions of the title occurred in 1822 and 1879. In effect, Armand Emmanuel du Plessis died without an heir, but he gained permission for the title of Duke of Richelieu to pass to the son of his half-sister Simplicie, daughter of Antoine-Pierre de La Chapelle de Saint-Jean de Jumilhac, with reversion to the descendants of his younger brother should he die without a male heir, thus effectively passing the title to his nephew.

The title became extinct in 1952 with the son of the 7th Duke of Richelieu and of Alice Heine (1858–1925). Alice was widowed in 1880 and remarried to prince Albert I of Monaco in 1889.