Peter of Luxembourg was count of Saint-Pol. His inheritance included the counties of Brienne, Conversano and Saint-Pol.
John, Lord of Beauvoir
…They had: Peter I of Luxembourg (1390 – 31 August 1433), Count of Saint-Pol and Count of Brienne John II of Luxembourg, Count of Ligny (1392 – 5 January 1441), inherited the title of…