The title Duke of Ayen (duc d'Ayen) was created by King Louis XV on 12 March 1737 raising the former county of Ayen to a Dukedom[1].
It was used as a courtesy title by the eldest son of the Duke of Noailles[2].
The lineage of Dukes of Ayen are cousins to the Dukes of Mouchy,[3] a cadet branch[4] of the House of Noailles[3].