The negotiations began after the return of peace and Henry IV's return to Catholicism. To support the invalidity of the marriage with the pope, the King and Margaret put forward the sterility of the couple, their consanguinity, and the formal defects of the marriage. During the talks, the queen’s financial situation improved, but she was displeased at the idea of Henry marrying his mistress, Gabrielle d'Estrees, mother of his son, César, who was legitimized in 1595, and refused to endorse what she considered to be a dishonorable remarriage: "It is repugnant to me to put in my place a woman of such low extraction and of so impure a life as the one about whom rumor speaks."