Margaret, Countess of Brienne

Marguerite d'Enghien, suo jure Countess of Brienne and of Conversano, suo jure Heiress of Enghien, and Lady of Beauvois (born 1365), was a wealthy noblewoman from the County of Hainaut in her own right, having inherited the counties of Brienne and of Conversano, and the Lordship of Enghien from her father Louis of Enghien on 17 March 1394. She was the wife of John of Luxembourg, Sire of Beauvois and the mother of Peter of Luxembourg, Count of Saint-Pol, Count of Brienne and of Conversano who inherited her fiefs, and John II of Luxembourg, Count of Ligny.

Marguerite was born in 1365, the eldest daughter of Louis of Enghien, Count of Brienne and of Conversano, Lord of Enghien, Titular Duke of Athens, and Giovanna of Sanseverino. She had three younger sisters, Yolande, Helene, and Isabelle. On 3 May 1384, Yolande married Philip of Bar (born 1372), who died in a Turkish prison in 1404 after being taken prisoner following the disastrous Battle of Nicopolis in 1396. Marguerite had a brother, Antoine who died at the age of sixteen, leaving her, the eldest daughter, heir to her father's estates and titles. Her paternal grandparents were Walter III of Enghien and Isabella of Brienne, and her maternal grandparents were Antonio of Sanseverino, 5th Count of Marsico, and Isabella del Balzo.

On an unknown date, Marguerite married her first husband, Pierre de Baux, and following his death, she married as her second husband, a relative of her mother, Giacopo of Sanseverino. Both of these early marriages were childless. In 1380, after Giacopo's death, Marguerite married her third husband, John of Luxembourg, Sire of Beauvois (1370–1397). He was the son of Guy of Luxembourg, Count of Saint-Pol and Mahaut of Châtillon, Countess of Saint-Pol. By her third husband, Marguerite had five children: