Marie I de Coucy, Countess of Soissons

In November 1384, she married Henry of Bar, Marquis de Pont-à-Mousson, son of Robert I, Duke of Bar and Marie of Valois, sister of King Charles V of France. The marriage produced two sons:

• Enguerrand of Bar (1387 – c. 1400)
• Robert of Bar, Count of Marle and Soissons (1390 – 25 October 1415), who died at the Battle of Agincourt.[2]

By the 15th century, Marie and her husband Henry moved to the Château de Condé, which had been in the Coucy family since the end of the 12th century.

Marie's mother, Isabella, died in 1379. Her father, Enguerrand, remarried in February 1386 to Isabelle, the daughter of John I, Duke of Lorraine. Upon Enguerrand's death on 18 February 1397 in a Turkish prison at Bursa, Anatolia, five months after the ferocious Battle of Nicopolis, Marie inherited his title and became the suo jure Countess of Soissons. Near the end of that same year, she was widowed. Her husband Henry was also taken prisoner at the Battle of Nicopolis and later ransomed.[3][4] In October 1397, on the lengthy journey home to France, Henry of Bar died at the Crusaders' camp in Treviso after having contracted the plague during his sojourn in Venice.[5] He was buried at the convent of the Celestines in Paris.

Marie disputed the wealthy de Coucy inheritance with her stepmother, with Marie claiming the entire inheritance, while Isabelle insisted upon receiving half. Neither of them yielded. The rich barony was described as "having castles of grandeur, with its 150 towns and villages, its famous forests, fine ponds, many good vassals, much great nobility and inestimable revenues". The women lived in mutual hostility, each in a separate castle of the domain, with her own captains and entourage of relatives, both of them endlessly pursuing lawsuits.

Marie was coerced by Louis d'Orléans into selling the barony to him in 1404. She brought at least eleven lawsuits against Orléans in an attempt to recover her property, but following a wedding feast which she had attended in 1405, Marie died suddenly. There were persistent rumours that she had been poisoned, but nothing could be proven to substantiate the allegations. Her son Robert continued the litigation, but eventually, the barony of Coucy passed to the French Crown.