John of Luxembourg (Jean de Luxembourg) (c. 1370 – 1397), was Lord of Beauvoir (or Beaurevoir) and Richebourg, and also (as John II) Count of Brienne and Conversano (iure uxoris).
He was a son of Guy I of Luxembourg, Count of Ligny and Mahaut de Châtillon (1335-1378), Countess of Saint-Pol.
John married around 1387 with Margaret, Countess of Brienne, daughter of Louis of Enghien, suo jure heiress of the counties of Brienne and of Conversano, and the Lordship of Enghien.
They had five children:
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 Beauvoir from his father, and the title of Ligny from his aunt, Jeanne of Luxembourg.
Louis of Luxembourg (died 18 September 1443). He was a statesman and a high-ranking churchman.
Catherine of Luxembourg (born c.1393)
Jeanne of Luxembourg (died 1420), married firstly, on 8 September 1415, Louis, Seigneur de Ghistelles (killed at the Battle of Agincourt); she married secondly on 28 October 1419, Jean IV, Viscount of Melun, Constable of Flanders.