In spite of the expectations of St. Mars that, in this mode of conveyance, his prisoner would have air enough, it appears that he complained of the want of it, and soon fell ill in consequence. This is mentioned in a letter of St. Mars, dated May 3d, 1687, giving an account of their arrival at the Island of St. Margaret, and is the last of the correspondence between Louvois and St. Mars respecting Matthioli: "I arrived here the 30th of last month. I was only twelve days on the journey, in consequence of the illness of my prisoner, occasioned, as he said, by not having as much air as he wished. I can assure you that no one has seen him, and that the manner in which I have guarded and conducted him during all the journey, makes every body try to conjecture who my prisoner is."[128]
It was probably, during this journey, that St. Mars first made use of a mask to hide the features of Matthioli.[129] Not as has been erroneously supposed a mask made of iron, which it will be evident, upon the slightest reflection, could not have been borne upon the face for any long continuance of time, but one of black velvet,[130] strengthened with whalebone, and fastened behind the head with a padlock, which did not prevent the prisoner from eating and drinking, or impede his respiration.[131]
The identity of Matthioli with the prisoner known by the name of "the Iron Mask," is here very satisfactorily confirmed by circumstantial evidence. We have seen that Matthioli and the Jacobin were placed together at Pignerol; we have seen that they were designated as "the two prisoners in the lower part of the tower;" we have seen that "the two prisoners in the lower part of the tower" were the only ones who accompanied St. Mars when his government was transferred to Exiles; we have seen the death of the Jacobin at the latter place; and now we find St. Mars conveying a single prisoner, designated as "_the prisoner_," with him to St. Margaret, with a repetition of the same precautions and of the same secrecy as on former occasions, to which are added the celebrated Mask. Who could this prisoner be but Matthioli? It is also observable, that in all the various accounts of the Iron Mask, though the dates are made to vary, he is always said to have been originally confined at Pignerol, subsequently at the island of St. Margaret, and finally to have accompanied St. Mars to the Bastille.