Although more people are familiar with Cardinal Richelieu, there was another famous Frenchman by that name, Louis François Armand de Vignerot du Plessis (1696-1788), duc de Richelieu. He inherited the duchy of Richelieu because its original owner, the Cardinal, left it to his nephew, Armand-Jean de Vignerot, with the stipulation that he take the family name du Plessis and the arms of Richelieu. Armand-Jean died in 1715, leaving the title to his son.

The duke was very popular and well-known for his gallant exploits at court, where he was a favorite companion of Louis XV. He was also known for his military successes, particularly during the Seven Years War. Nevertheless, he was sent to the Bastille several times, the first by Louis XIV, for being too devoted to the beauty of the duchess of Burgundy. He was also out of favor at court for some time for refusing to allow his son to marry Mme de Pompadour's daughter.

Richelieu is the ideal of the 18th-century French nobleman/libertine, who lived by privilege, exploits, and adultery. He died one year before the Revolution.