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.

Boniface, 1st sovereign baron[1] de Castellane, lived in the 11th century.

The sovereign barons de Castellane ruled over a small state[2] 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."

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.