The Cardinal-Infant died of a tertian fever (9th November 1641), which had not hindered his remaining in the army all through the campaign.... His malady had not appeared very dangerous; nevertheless he died a few days after he came back from Brussels; which made them say that the Spaniards had poisoned him because they were afraid that by forming an alliance with France he would render himself master of Flanders,[78] and, in fact, that was his design. The Queen told me that after the King died she found in his strong-box memoranda showing that my marriage with that Prince had been decided upon. She told me nothing but that ... when this loss came upon them the King said to the Queen ... and he said it very rudely--"Your brother is dead." That news, so coarsely announced, added to her grief ... and for my own part, when I reflected upon my interests I was very deeply grieved; because that would have been the most agreeable establishment in the world for me, because of the beauty of the country, lying as it does so near this country, and because of the way in which they live there. As for the qualities of his person, though I esteemed him much, that was the least that I thought of. The disappearance of the Cardinal-Infant was followed by events so tragic and so closely connected with Mademoiselle's life that her mind was distracted from her hunt for a husband. Despite her extreme youth, the affair Cinq-Mars constrained her to judge her father, and to the child to whom nothing was as dear as honour the revelation of his treachery was crushing. IV The death of Cinq-Mars was the dénouement of a great and tragic passion. Henry d'Effiat, Marquis de Cinq-Mars, was described as a handsome youth with soft, caressing eyes, marvellously graceful in all his movements.[79]