Duke of Fronsac (French: duc de Fronsac) was a title of French nobility, first created by promoting the seigneurie of Fronsac to a duchy in 1608, but the title became extinct a few decades later. This title was revived in 1634 for Armand Jean du Plessis de Richelieu, better known as Cardinal Richelieu, and it survived until the 19th century.

First creation

The title of duc de Fronsac was first created in 1608 for the House of Longueville, a bastard-cadet branch of the House of Valois. The mother of the first duke, Anne de Caumont (1574–1642), held the lesser title of marquis de Fronsac when her son Léonor II d'Orléans was created a duke. The title became extinct after the first duke died without an heir and the title passed to his father, who had no other issue.

Second creation

In 1634, the title of duc de Fronsac was revived for Armand Jean du Plessis de Richelieu, who already held the title of Duke of Richelieu. The title of Duke of Fronsac was often used by subsequent Dukes of Richelieu as a titre d'attente, or courtesy title, for the heir to the Dukedom of Richelieu.