Now it happened that one of his London agents informed him, among other matters connected with the Duke’s private life, that he had a bitter and secret enemy in the Countess of Carlisle, between whom and himself there had been a passage of some tenderness too abruptly ended by the Duke. Richelieu, acting upon this information, contrived to enter into correspondence with Lady Carlisle, and in the course of this correspondence he managed her so craftily—says La Rochefoucauld—that very soon she was, whilst hardly realizing it, his Eminence’s most valuable spy near Buckingham. Richelieu informed her that he was mainly concerned with information that would throw light upon the real relations of Buckingharn and the Queen of France, and he persuaded her that nothing was too insignificant to be communicated. Her resentment of the treatment she had received from Buckingham, a resentment the more bitter for being stifled—since for her reputation’s sake she dared not have given it expression—made her a very ready instrument in Richelieu’s hands, and there was no scrap of gossip she did not carefully gather up and dispatch to him. But all was naught until one day at last she was able to tell him something that set his pulses beating more quickly than their habit. She had it upon the best authority that a set of diamond studs constantly worn of late by the Duke was a love-token from the Queen of France sent over to Buckingham by a messenger of her own. Here, indeed, was news. Here was a weapon by which the Queen might be destroyed. Richelieu considered. If he could but obtain possession of the studs, the rest would be easy. There would be an end—and such an end!—to the King’s obstinate, indolent faith in his wife’s indifference to that boastful, flamboyant English upstart. Richelieu held his peace for the time being, and wrote to the Countess.