This is very likely, since GRR Martin has aknowledged beeing a fan of Maurice Druon's Accursed Kings (Les Rois Maudits) historical saga about kings of France from 1314 to 1361, which includes this plot. In 1314, Margerite de Bourgogne (Margaery ?), wife of Louis, future king of France (he will be Louis X le Hutin), is accused of adultery with knights at the court, together with her cousin and close friend Blanche de Bourgogne, married to Charles, youngest brother of the future king (he eventually will be king as well, as Charles IV le Bel). They are denouced by Isabelle de France, wife of Edward II king of England. The trial sentences the two knights to be skinned alive, castrated (their sexes thrown to dogs) and eventually beheaded, their body exposed on gallows. The fate of the two women is different : they have their head shaved, are displayed to the crowd, humiliated in the streets, and then locked up in dungeons. Another cousin, Jeanne de Bourgogne, present at the court, is not convinced of adultery but found guilty of having not denouced her two cousins by herself. She is sent to spend the rest of her life in a remote castle. Blanche de Bourgogne will be allowed to leave her prison, have her marriage cancelled and become a nun after seven years. Marguerite de Bourgogne will die some months after the trial, because of the coldness of her cell, although it is said that she has been secretely strangled, having become an obstacle for a new marriage of the king of France.
