The decree of the Court of justice, dated 20th December 1664, banished Fouquet from the kingdom for life.  “But the king was of the opinion that it would be dangerous to let the said Fouquet leave the country, in consideration of his intimate knowledge of the most important matters of state.  Consequently the sentence of perpetual banishment was commuted into that of perpetual imprisonment.” (’Receuil des defenses de M. Fouquet’).  The instructions signed by the king and remitted to Saint-Mars forbid him to permit Fouquet to hold any spoken or written communication with anyone whatsoever, or to leave his apartments for any cause, not even for exercise.  The great mistrust felt by Louvois pervades all his letters to Saint-Mars.  The precautions which he ordered to be kept up were quite as stringent as in the case of the Iron Mask.

The report of the discovery of a shirt covered with writing, by a friar, which Abbe Papon mentions, may perhaps be traced to the following extracts from two letters written by Louvois to Saint-Mars:  “Your letter has come to hand with the new handkerchief on which M. Fouquet has written” (18th Dec. 1665 ); “You can tell him that if he continues too employ his table-linen as note-paper he must not be surprised if you refuse to supply him with any more” ( 21st Nov. 1667).

Pere Papon asserts that a valet who served the masked prisoner died in his master’s room.  Now the man who waited on Fouquet, and who like him was sentenced to lifelong imprisonment, died in February 1680 (see letter of Louvois to Saint-Mars, 12th March 1680).  Echoes of incidents which took place at Pignerol might have reached the Iles Sainte-Marguerite when Saint-Mars transferred his “former prisoner” from one fortress to the other.  The fine clothes and linen, the books, all those luxuries in fact that were lavished on the masked prisoner, were not withheld from Fouquet.  The furniture of a second room at Pignerol cost over 1200 livres (see letters of Louvois, 12th Dec. 1665, and 22nd Feb, 1666).

It is also known that until the year 1680 Saint-Mars had only two important prisoners at Pignerol, Fouquet and Lauzun.  However, his “former prisoner of Pignerol,” according to Du Junca’s diary, must have reached the latter fortress before the end of August 1681, when Saint-Mars went to Exilles as governor.  So that it was in the interval between the 23rd March 1680, the alleged date of Fouquet’s death, and the 1st September 1681, that the Iron Mask appeared at Pignerol, and yet Saint-Mars took only two prisoners to Exilles.  One of these was probably the Man in the Iron Mask; the other, who must have been Matthioli, died before the year 1687, for when Saint-Mars took over the governorship in the month of January of that year of the Iles Sainte-Marguerite he brought only one prisoner thither with him.  “I have taken such good measures to guard my prisoner that I can answer to you for his safety” (’Lettres de Saint-Mars a Louvois’, 20th January 1687).