Joan, Countess of Ligny

Joan, Countess of Saint-Pol and Ligny (d. 18 September 1430, Avignon), called the Demoiselle de Luxembourg, was the daughter of Guy of Luxembourg, Count of Ligny and Mahaut of Châtillon, Countess of Saint-Pol.
At the death of Philip I, Duke of Brabant, she was his nearest living relative on the Saint-Pol side, and inherited Saint-Pol and Ligny upon his death on 14 August 1430. She was living at the time at Beaurevoir, which belonged to her favorite nephew John. At this time, John held Joan of Arc, whom he had captured, as a prisoner. The Demoiselle de Luxembourg showed kindness to her, and pleaded with her nephew not to sell Joan to the English. The Demoiselle died shortly thereafter; her fiefs were divided between her senior nephew, the Count of Brienne, who received Saint-Pol, and John, her favorite, who received Ligny.
The Demoiselle is a character in Philippa Gregory's 2011 historical novel The Lady of the Rivers, which centers on her great-niece Jacquetta of Luxembourg.