Beatrice, Countess of Montfort  Beatrice de Montfort, Countess of Montfort-l'Amaury (c. December 1248/1249 – 9 March 1312) was a ruling sovereign countess of Montfort from 1249 until 1312. She was also countess of Dreux by marriage to Robert IV of Dreux, Count of Dreux. She was the ancestor of the Dukes of Brittany from the House of Montfort-Dreux which derived its name from her title. Beatrice was born sometime between December 1248 and 1249, the only child of Jean I de Montfort, Count of Dreux and Jeanne, Dame de Chateaudun. In 1249, Beatrice's father died in Cyprus, while participating in the Seventh Crusade. Thus, Beatrice succeeded her father as ruling count of Montfort at the age of about one years old. In 1251, Jeanne married her second husband, Jean de Brienne, Grand Butler of France. Jeanne and Jean had a daughter Blanche de Brienne, Baroness Tingry (1252–1302); Blanche married William II de Fiennes, Baron of Tingry. Jeanne died sometime after 1252, leaving her Beatrice and her half-sister Blanche as her co-heiresses. Beatrice was married to Robert IV of Dreux, Count of Dreux, Braine and Montfort-l'Amaury in 1260, when she was about eleven years old. He was the son of John I of Dreux, Count of Dreux and Braine, and Marie de Bourbon. As was the custom for female rulers at this point in time, he became the co-ruler of Beatrice and Count of Montfort by right of his wife after their wedding. Beatrice died on 9 March 1312 at the age of sixty-three. She was buried in the Abbaye de Haute- Bruyère.