It is a French title of nobility, referring to a noble who holds the duchy of Langeais.
Here's what you need to know:
* Langeais: This is a commune and a historical castle located in the Indre-et-Loire department of the Centre-Val de Loire region in France.
* Duc: This is the French word for "duke," a title historically given to rulers of a duchy.
In literature and history:
* The title has been used in several literary works: One notable example is Honoré de Balzac's novel, "The Duchess of Langeais" (La Duchesse de Langeais), which tells the story of a noblewoman and her relationship with a dashing military officer.
* The title "Duc de Langeais" might also be used to refer to a specific historical figure: There have been several individuals throughout history who have held this title, though their specific identities and legacies might not be as widely known as the fictional character in Balzac's work.
Therefore, the meaning of "Duc de Langeais" is primarily tied to the noble title and the associated historical and literary context. It suggests an individual of high social standing and potentially with a significant connection to the Château de Langeais.