On 11 June 1642, while in Tarascon on one of the long military expeditions, Mazarin was presented with evidence that Gaston, Duke of Orléans, the brother of Louis XIII, and The Marquis of Cinq-Mars, one of the King's closest advisors, had made a secret agreement with the King of Spain, without the knowledge of Richelieu or the King. It appeared probable that the Queen, Anne of Austria, was also aware of this secret betrayal of Richelieu, but did not tell him or the King. Cinq-Mars was arrested, Gaston was disgraced, and another conspirator, the Duke of Bouillon, was granted a pardon on the condition of revealing all the details of the plot to Mazarin, and surrendering the important fortress of Sedan to the King. Mazarin did not reveal the participation of the Queen in the conspiracy, but his knowledge gave him even greater leverage at the court.