According to M. de Saint-Mihiel, the ’Man in the Iron Mask was a legitimate son of Anne of Austria and Mazarin’.

He avers that Mazarin was only a deacon, and not a priest, when he became cardinal, having never taken priest’s orders, according to the testimony of the Princess Palatine, consort of Philip I, Duc d’Orleans, and that it was therefore possible for him to marry, and that he did marry, Anne of Austria in secret.

“Old Madame Beauvais, principal woman of the bed-chamber to the queen mother, knew of this ridiculous marriage, and as the price of her secrecy obliged the queen to comply with all her whims.  To this circumstance the principal bed-chamber women owe the extensive privileges accorded them ever since in this country” (Letter of the Duchesse d’Orleans, 13th September 1713).

“The queen mother, consort of Louis xiii, had done worse than simply to fall in love with Mazarin, she had married him, for he had never been an ordained priest, he had only taken deacon’s orders.  If he had been a priest his marriage would have been impossible.  He grew terribly tired of the good queen mother, and did not live happily with her, which was only what he deserved for making such a marriage” (Letter of the Duchesse d’Orleans, 2nd November 1717).

“She (the queen mother) was quite easy in her conscience about Cardinal Mazarin; he was not in priest’s orders, and so could marry.  The secret passage by which he reached the queen’s rooms every evening still exists in the Palais Royal” (Letter of the Duchesse d’Orleans, 2nd July 1719)

“The queen’s, manner of conducting affairs is influenced by the passion which dominates her.  When she and the cardinal converse together, their ardent love for each other is betrayed by their looks and gestures; it is plain to see that when obliged to part for a time they do it with great reluctance.  If what people say is true, that they are properly married, and that their union has been blessed by Pere Vincent the missioner, there is no harm in all that goes on between them, either in public or in private” (’Requete civile contre la Conclusion de la Paix, 1649).

The Man in the Iron Mask told the apothecary in the Bastille that he thought he was about sixty years of age (’Questions sur d’Encyclopedie’).  Thus he must have been born in 1644, just at the time when Anne of Austria was invested with the royal power, though it was really exercised by Mazarin.

Can we find any incident recorded in history which lends support to the supposition that Anne of Austria had a son whose birth was kept as secret as her marriage to Mazarin?

“In 1644, Anne of Austria being dissatisfied with her apartments in the Louvre, moved to the Palais Royal, which had been left to the king by Richelieu.  Shortly after taking up residence there she was very ill with a severe attack of jaundice, which was caused, in the opinion of the doctors, by worry, anxiety, and overwork, and which pulled her down greatly” (’Memoire de Madame de Motteville, 4 vols. 12mo, Vol i. p. 194).