One formidable rival thus removed from her path, Madame de Soissons was not long left to enjoy her triumph; for another was quick to take the place abandoned by the broken-hearted Marie—­the beautiful and gentle La Valliere, who was the next to acquire an ascendancy over the King’s susceptible heart.  Once more the Comtesse, to her undisguised chagrin, found herself relegated to the background, to look impotently on while Louis made love to her successor, and to meditate new schemes of vengeance.  It was in vain that Louis, by way of amende, found for her a lover in the Marquis de Vardes, the most handsome and dissolute of his courtiers, for whom she soon developed a veritable passion.  Her vanity might be appeased, but her bitterness—­the spretoe injuria formoe—­remained; and she lost no time in plotting further mischief.

With the help of M. de Vardes and the Comte de Guiche, she sent an anonymous letter to the Queen, containing a full and intimate account of her husband’s amour with La Valliere—­the letter enclosed in an envelope addressed in the handwriting of the Queen of Spain.  Fortunately for Maria Theresa’s peace of mind the letter fell into the hands of Louis himself, who was naturally furious at such treachery and determined to make those responsible for it suffer—­when he should discover them.  As, however, the investigation of the matter was entrusted to de Vardes, it is needless to say that the culprits escaped detection.

Madame de Soissons’ next attempt to bring about a rupture between the King and La Valliere, by bringing forward a rival in the person of the seductive Mlle de la Motte-Houdancourt, proved equally futile, when Louis discovered by accident that she was but a tool in Madame’s designing hands; and for a time the Comtesse was sent in disgrace from the Court to nurse her jealousy and to devise more effectual plans of vengeance.

What form these took seems clear from an investigation held at the close of 1678 into a supposed plot to poison the King and the Dauphin—­a plot of which La Voisin, one of the greatest criminals in history, was suspected of being the ringleader.  During this inquiry La Voisin confessed that the Comtesse de Soissons had come to her house one day “and demanded the means of getting rid of Mile de la Valliere”; and, further, that the Comtesse had avowed her intention to destroy not only Louis’ mistress, but the King himself.

Such a confession was well calculated to rouse a storm of indignation in France, where Madame de Soissons had made many powerful enemies.  The Chambre unanimously demanded her arrest; but before it could be effected, Madame, stoutly declaring her innocence, had shaken the dust of Paris off her feet, and was on her way to Brussels.