|Date of birth|
|Date of death||Dec 06, 1641 Broc|
Françoise de Montmorency-Fosseux (1566 – 6 December 1641), also called "La Belle Fosseuse" or "La Fosseuse", was mistress to King Henry III of Navarre (future King Henry IV of France) from 1579 to 1581.
Françoise de Montmorency-Fosseux was the youngest of five daughters born to Pierre I de Montmorency. At age thirteen, she became lady-in-wating to Queen Margaret of Valois. A shy and blushing girl, she caught the attentions of King Henry. He called her "ma fille" and plied her with cakes, pastries, and rosewater sweets. She finally gave in to his advances during a voyage to Montauban, and afterwards grew ambitious and arrogant towards Queen Margaret, carrying on the affair in hopes of marriage. She eventually became pregnant, and with the prospect of bearing the child of a king, came to consider herself queen. Wary of gossip, however, she and Henry fled court at Nérac for Eaux-Chaudes from 7 to 25 June 1581. Henry wanted Queen Margaret to travel with them, but she waited to join the two at Bagnères de Bigorre. Margaret proposed banishing her rival from court, but La Fosseuse screamed that she would refuse to cooperate.
Françoise finally gave birth to a daughter, but the child was stillborn. The doctor informed Henry, and Margaret made sure the lying-in proceeded as discreetly as possible by acting as midwife. Margaret was then invited by her mother Catherine de' Medici to Paris, along with her ladies-in-waiting, including Françoise. Catherine advised her daughter to return Françoise to her own parents. Following this counsel, Margaret chased La Fosseuse from court in 1582. Henry took this as a personal insult, but did nothing to retaliate, as he had then fallen to the charms of "the beautiful Corisande," Diane d'Andoins.
On 11 March 1596, Françoise de Montmorency-Fosseux married François de Broc, Baron of Cinq-Mars. At her death in 1614, she was buried in the church at Broc.