Margaret 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 marriedher 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:

• Peter of Luxembourg (1390- 31 August 1433), Count of Saint-Pol (1430), which he inherited from his aunt Jeanne of Luxembourg, Countess of Saint-Pol and Ligny; he also inherited, on an unknown date, Marguerite's fiefs of Brienne and of Conversano, thus becoming Count of Brienne and of Conversano. He married on 8 May 1405, Margaret de Baux, by whom he had nine children, including Jacquetta of Luxembourg, mother of Elizabeth Woodville Queen-Consort of Edward IV of England.
• John II of Luxembourg, Count of Ligny (1392- 5 January 1441), inherited the title of Beauvois from his father, and the title of Ligny from his aunt, Jeanne of Luxembourg. On 23 November 1418, married Jeanne de Béthune, widow of Robert of Bar, Count of Marle and Soissons who had been killed at the Battle of Agincourt on 25 October 1415. John, who was an ally of the English during the Hundred Years War, received Joan of Arc as his prisoner, and subsequently sold her to the English for 10,000 livres.
• Louis of Luxembourg (died 18 September 1443). He was a statesman and a high-ranking churchman. His posts and clerical titles included Cardinal (1439), Archbishop of Rouen (1437), Chancellor of France (1425), Governor of Paris (1436), Bishop of Thérouanne, Administrator of Ely (1437), Bishop of Frascati (1442). He was buried in Ely Cathedral.
• 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.

Marguerite became the suo jure Countess of Brienne and Conversano, and Dame of Enghien upon her father's death on 17 March 1394. Her husband John also became Count of Brienne and of Conversano by right of his wife.

She died on an unknown date sometime after 1394. Her will was dated 19 September 1393. Her eldest son, Peter received her titles of Brienne and of Conversano.

Through her son Peter and his wife, Margaret de Baux, Marguerite was an ancestress of Queen consort Elizabeth Woodville and her siblings, King Henry VIII of England, and King Henry IV of France.