He might, however, as the event proved, have been more deliberate in his movements; for Monsieur, already annoyed by the disappointment to which he had been subjected, evinced no disposition to profit by the brief opportunity thus afforded to him, but proceeded leisurely to Dauphiny; where he had no sooner arrived than he received information that the most strenuous efforts had been made immediately after he had left Paris to hasten the departure of Marie de Gonzaga.  Delighted at any pretext for abandoning the journey to which he had been compelled, he forthwith retraced his steps; but great as was the haste which he displayed to reach the capital, the first news by which he was greeted was that the Queen-mother had caused the Princess of Mantua to be imprisoned in the fortress of Vincennes.

This extraordinary intelligence was communicated to him by the Marechal de Marillac, who had succeeded Richelieu in the confidence of Marie de Medicis; and who endeavoured to palliate the outrage by explaining the motives which induced her Majesty to take so singular a step.  She had been as M. de Marillac asserted, assured that his Highness had resolved to carry off Mademoiselle de Gonzaga, and then to leave the kingdom; a determination by which she was so much alarmed that she had adopted the only measure which had appeared to her to offer a certain preventive to so dangerous and unprecedented a proceeding; but Monsieur would listen to no arguments upon the subject, and withdrew in violent displeasure to Orleans, whence he despatched one of the officers of his household to protest against the imprisonment of the Princess, and to demand not only that she should immediately be set at liberty, but also that she should not be permitted to leave the country.

The Queen-mother, who was aware that she could not justify a proceeding which violated all the rights of hospitality, and who was, moreover, alarmed lest she should incur the lasting animosity of her favourite son, and thus render herself still more helpless than she had already become through the defection of Richelieu, found herself compelled to accede to a request which had in fact assumed the character of a command; but she, nevertheless, only accorded her consent to the release of the captive on condition that Monsieur should desist, for a time at least, in pressing his marriage either with Marie de Gonzaga or any other Princess until he had received the consent of the King to that effect; and Gaston having, after some hesitation, agreed to the proposed terms, the unfortunate girl was removed from Vincennes to the Louvre, whither the Prince immediately hastened to congratulate her on her liberation, and to express to the Queen-mother his indignation at what had occurred.[113]