Carte blanche never breaks bad for me.
Shortly after this was published in book form with the same signature a second novel, Rose et Blanche.
John was first married to Blanche of Navarre, of the house of Evreux.
Charles's first wife was Blanche, daughter of Otto IV., count of Burgundy, and of Matilda (Mahaut), countess of Artois, to whom he was married in 1307.
Blanche was still in prison when Charles became king.