Man in the Iron Mask Dumas also presented a review of the popular theories about the prisoner extant in his time in the chapter "L'homme au masque de fer" in the sixth volume of his non-fiction "Crimes Célèbres". The earliest surviving records of the masked prisoner are from late July 1669, when Louis XIV's minister, the Marquis de Louvois, sent a letter to Bénigne Dauvergne de Saint-Mars, governor of the prison of Pignerol, which at the time was part of France. In his letter, Louvois informed Saint-Mars that a prisoner named "Eustache Dauger" was due to arrive in the next month or so. Louvois instructed
Man in the Iron Mask for instance, if Fouquet and Lauzun were to meet, Dauger was not to be present. It is an important point that the man in the mask served as a valet. Fouquet was never expected to be released; thus, meeting Dauger was no great matter, but Lauzun was expected to be set free eventually, and it would have been important not to have him spread rumours of Dauger's existence. Historians have also argued that 17th-century protocol made it unthinkable that a man of royal blood would serve as a manservant, casting some doubt on speculation that Dauger was in some way