Margaret of Valois was a twin.
Margaret of Valois . A daughter of King Henry II of France and Catherine de ' Medici , Margaret was the sister of kings Francis II , Charles IX and Henry III , and of Elisabeth of Valois Queen of Spain , as well as Claude of Valois . While imprisoned , she took advantage of the time to write her memoirs , which included a succession of stories relating to the disputes of her brothers Charles IX and Henry III with her husband .