Valentinois (duchy of) - Romans-sur-Isère

The Duchy of Valentinois was formed through the temporal powers of the Bishops of Valence, who for centuries passed down the title from uncle to nephew before, at the beginning of the 12th century, bequeathing the diocese to the House of Poitiers who, two centuries later, acquired the Earldom (Comté) of Diois from the Orange branch of the House of Baux.

Through shrewd politics, the Counts of Valentinois and Diois expanded their estates, but as a result of their continual conflict with the Bishops of Die and Valence, upon the death of Louis II of Poitiers in 1419, they were finally forced to concede their lands to the King of France.
After a long period of unrest, disputes, wars and trials, the Comtés of Valentinois and Diois were established as the Duchy of Valentinois in the name of Cesare Borgia. After Borgia’s treason, the Duchy was then given to Diane of Poitiers who brought renewed splendour to her fiefdom. Upon her death, Valentinois was returned to the Crown and became the stage for particularly violent, and mainly religious, wars.

The country was in a time of relative peace when, following the signing of the Treaty of Péronne on 14 September 1641 by King Louis XIII, it was re-established as a dukedom and bestowed to Honoré II, Prince of Monaco. However, the estate remained disproportionate to the former Comté of Valentinois and to the Duchies of César Borgia or Diane of Poitiers. It was effectively made up of lands (the Lordships of Crest, Grâne, Sauzet and Savasse; the Barony of Buis; and the estates of Montélimar, Chabeuil and Romans), seigniorial rights and feudal tolls and income. Valence, the capital of the region, was not included in the Duchy and the electoral centre of Montélimar was to serve as capital in its place.

Although the successor to the throne was traditionally given the title of Marquis of Baux, from the end of the 17th century until the marriage of Princess Charlotte, grandmother of the current sovereign, in 1920, the title of Duke of Valentinois was also held by the princes before their succession.