Man in the Iron Mask

The Man in the Iron Mask (French: L'Homme au Masque de Fer; died 19 November 1703) was an unidentified prisoner of state during the reign of Louis XIV of France (1643–1715). The strict measures taken to keep his imprisonment secret resulted in a long-lasting legend about his identity. Warranted for arrest on 19 July 1669 under the pseudonym of "Eustache Dauger", he was apprehended near Calais on 28 July, incarcerated on 24 August, and held for 34 years in the custody of the same jailer, Bénigne Dauvergne de Saint-Mars, in four successive French prisons, including the Bastille. When he died there on 19 November 1703, his inhumation certificate bore the pseudonym of "Marchioly", leading several historians to conclude the prisoner was Italian diplomat Ercole Antonio Mattioli.

His true identity remains a mystery, even though it has been extensively debated by historians, and various theories have been expounded in numerous books, articles, poems, plays, and films. During his lifetime, it was rumoured that he was a Marshal of France or a President of Parlement; the Duke of Beaufort, or a son of Oliver Cromwell. Among the oldest theories is one proposed by French philosopher and writer Voltaire, who claimed in his Questions sur l'Encyclopédie (1771) that the prisoner was an older, illegitimate brother of Louis XIV. Other writers similarly believed he was the King's twin or younger brother. In all, more than 50 candidates, real and hypothetical, have been proposed by historians and other authors aiming to solve the mystery.

What little is known about the prisoner is based on contemporary documents uncovered during the 19th century, mainly some of the correspondence between Saint-Mars and his superiors in Paris, initially Louvois, Louis XIV's secretary of state for war. These documents show that the prisoner was labelled "only a valet" and that he was jailed for "what he was employed to do" before his arrest. Legend has it that no one ever saw his face, as it was hidden by a mask of black velvet cloth, later misreported by Voltaire as an iron mask. Official documents reveal, however, that the prisoner was made to cover his face only when travelling between prisons after 1687, or when going to prayers within the Bastille in the final years of his incarceration; modern historians believe the latter measure was imposed by Saint-Mars solely to increase his own prestige, thus causing persistent rumours to circulate about this seemingly important prisoner.

In 1932, French historian Maurice Duvivier proposed that the prisoner was Eustache Dauger de Cavoye, a nobleman associated with several political scandals of the late 17th century. This solution, however, was disproved in 1953 when previously unpublished family letters were discovered by another French historian, Georges Mongrédien, who concluded that the enigma remained unsolved owing to the lack of reliable historical documents about the prisoner's identity and the cause of his long incarceration.

He has been the subject of many works of fiction, most prominently in 1850 by Alexandre Dumas. A section of his novel The Vicomte of Bragelonne: Ten Years Later—the final installment of his D'Artagnan saga—features this prisoner, portrayed as Louis XIV's identical twin and forced to wear an iron mask. In 1840, Dumas had first presented a review of the popular theories about the prisoner extant in his time in the chapter "L'homme au masque de fer", published in the eighth volume of his non-fiction Crimes Célèbres. This approach was adopted by many subsequent authors, and speculative works have continued to appear on the subject.