The Man in the Iron Mask (French: LHomme au Masque de Fer) (died 19 November 1703) was a prisoner who was held in a number of jails, including the Bastille and the Fortress of Pinerolo, during the reign of Louis XIV of France. The identity of this man has been thoroughly discussed and been the subject of many books, mainly because no one ever saw his face, which was hidden by a mask of black velvet cloth.
In his Questions sur lEncyclopédie (French for "Questions on the Encyclopaedia"), published in 1771, the writer and philosopher Voltaire claimed that the prisoner wore an iron mask and was the older, illegitimate brother of Louis XIV. In the late 1840s, the writer Alexandre Dumas elaborated on the theme in the final installment of his Three Musketeers saga: here the prisoner is forced to wear an iron mask and is Louis XIVs twin brother.
What actual facts are known about this prisoner are based mainly on correspondence between his jailer and his superiors in Paris.