The House of Castellane is a very ancient French noble house originating in Provence and descended from Thibault, count of Arles in the 9th century.
History
Boniface, 1st sovereign baron de Castellane, lived in the 11th century. The sovereign barons de Castellane ruled over a small state bordering the Haute-Provence until the beginning of the 13th century, rendering homage to their overlord the count of Provence.
Even after this they retained de jure sovereignty: "
"Even after having been forced to pay homage to the Counts of Provence, these powerful feudal lords retained the fullness of the authority they exercised over their vassals."
According to Lumens (Histoire de Castellane, published by J.-B. Shares...[t]he town, the castle and the rock of Castellane and declared him sovereign after the example of his elders;
In 1993, king Juan Carlos I rehabilitated the title of Duke of Almazán de Saint Priest on a descendant of the first duke, Louis Provence Boniface de Castellane (1912–1996), who became the 2nd Duke de Almazán de Saint Priest, with his daughter Béatrice Marguerite Marie-Thérèse de Castellane (b. 1944) following him as 3rd Duchess de Almazán de Saint Priest.