Which mysterious prisoner was held in the Bastille for many years?

The mysterious prisoner held in the Bastille for many years was known as the Man in the Iron Mask.

He was an unidentified state prisoner under Louis XIV. Records show that he was transferred to the Bastille in 1698 and died there in 1703, after spending decades in several French prisons. The Bastille was therefore the final stage of his confinement, not the place where he spent his entire imprisonment.

Historical documents identify him at different points with names including Eustache Dauger and, at burial, “Marchioly,” but his true identity remains unresolved. More than 50 candidates have been proposed, including the Italian diplomat Ercole Antonio Mattioli. The popular theory that he was Louis XIV’s twin brother comes mainly from later literary treatments, especially those associated with Voltaire and Alexandre Dumas, rather than secure contemporary evidence.

The “iron” mask is also partly a legend. Sources indicate that the covering was probably black velvet and was used especially during transfers or public appearances. The enduring mystery made him one of France’s most famous prisoners.