Duke of Valentinois

Both the Italianized form of this title and his previous appointment as Cardinal of Valencia led to his commonly used nickname: "Il Valentino".

King Henry II of France created his mistress Diane de Poitiers Duchess of Valentinois in 1548.

She was the only suo jure Duchess and her title was destinated to end after her death, due to the Salic law commonly used among French nobility.

King Louis XIII of France created the title by letters patent, signed in May 1642 and registered on 18 July 1642, as a conglomeration of several estates in the French province of Dauphiné which he had previously given to Honoré II, Prince of Monaco.

On 20 October 1715, Antoine's eldest daughter and heiress Louise-Hippolyte married Jacques-François de Goyon-Matignon, who had signed a contract on 5 September 1715 by which he was obliged to take the surname Grimaldi.