After reading the arguments of the advocates of Mattioli, I could not but perceive that, whatever captive died, masked, at the Bastille in 1703, the valet Dauger was the real source of most of the legends about the Man in the Iron Mask. A study of M. Lair’s book ‘Nicholas Foucquet’ (1890) confirmed this opinion. I therefore pushed the inquiry into a source neglected by the French historians, namely, the correspondence of the English ambassadors, agents, and statesmen for the years 1668, 1669.* One result is to confirm a wild theory of my own to the effect that the Man in the Iron Mask (if Dauger were he) may have been as great a mystery to himself as to historical inquirers. He may not have known WHAT he was imprisoned for doing! More important is the probable conclusion that the long and mysterious captivity of Eustache Dauger, and of another perfectly harmless valet and victim, was the mere automatic result of the ‘red tape’ of the old French absolute monarchy. These wretches were caught in the toils of the system, and suffered to no purpose, for no crime. The two men, at least Dauger, were apparently mere supernumeraries in the obscure intrigue of a conspirator known as Roux de Marsilly. *The papers are in the Record Office; for the contents see the following essay, ‘The Valet’s Master.’ This truly abominable tragedy of Roux de Marsilly is ‘another story,’ narrated in the following essay. It must suffice here to say that, in 1669, while Charles II. was negotiating the famous, or infamous, secret treaty with Louis XIV.--the treaty of alliance against Holland, and in favour of the restoration of Roman Catholicism in England--Roux de Marsilly, a French Huguenot, was dealing with Arlington and others, in favour of a Protestant league against France. When he started from England for Switzerland in February 1669, Marsilly left in London a valet, called by him ‘Martin,’ who had quitted his service and was living with his own family. This man is the ‘Eustache Dauger’ of our mystery. The name is his prison pseudonym, as ‘Lestang’ was that of Mattioli. The French Government was anxious to lay hands on him, for he had certainly, as the letters of Marsilly prove, come and gone freely between that conspirator and his English employers. How much Dauger knew, what amount of mischief he could effect, was uncertain. Much or little, it was a matter which, strange to say, caused the greatest anxiety to Louis XIV. and to his Ministers for very many years. Probably long before Dauger died (the date is unknown, but it was more than twenty-five years after Marsilly’s execution), his secret, if secret he possessed, had ceased to be of importance. But he was now in the toils of the French red tape, the system of secrecy which rarely released its victim. He was guarded, we shall see, with such unheard-of rigour, that popular fancy at once took him for some great, perhaps royal, personage.