Duke of Valentinois

Duke of Valentinois (French: Duc de Valentinois; Italian: Duca Valentino), formerly Count of Valentinois, is a title of nobility, originally in the French peerage. Though the duchy was once associated with administrative authority as well as possession of manors in Valence in France's Ancien Régime, those noble prerogatives were whittled away and by the 20th century it was a nominal dukedom consisting of a hereditary title descending in the male line.

It was created at least four times: on August 17, 1498, for Cesare Borgia, in 1548 for Diane de Poitiers, in 1642 for Honoré II, Prince of Monaco, and most recently in 1715 for Prince Jacques I of Monaco. Despite the fact that Jacques I's descendants became extinct in the male line in 1949, the dukedom is still used as a subsidiary title by the Prince of Monaco.

The county of Valentinois was a fief within the Dauphiné of Viennois and part of the Holy Roman Empire since 1032. Its owners were powerful lords during the Middle Ages and the Renaissance. During the fifteenth century, the dauphins from the House de La Tour du Pin engaged in several conflicts on behalf of the Valois kings of France. The last dauphin, Humbert II de la Tour-du-Pin, depleted his treasury funding an unsuccessful crusade to conquer the Holy Land and sold his lands to the highest bidder after his only son's death. Philip VI of France bought the Dauphiné in 1349 for 400,000 écus and an annual pension. To keep up appearances however, the sale was referred to as a "transfer". In order to prevent the title from going extinct, Humbert instituted a statute whereby the Dauphiné was exempted from many taxes. This statute was subject to much parliamentary debate at the regional level, as local leaders sought to defend their autonomy and privilege against the state.

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