Duke of Rohan is a title of French nobility, associated with the Breton region of Rohan.
House of Rohan-Chabot
The title prince de Léon is used a courtesy title until the succession of the duke.
References
Duke of Rohan Wikipedia(Text) CC BY-SA
Duke of Rohan is a title of French nobility, associated with the Breton region of Rohan.
The title prince de Léon is used a courtesy title until the succession of the duke.