Isabelle of France (March 1225 – 23 February 1270) was a French princess and daughter of Louis VIII of France and Blanche of Castile. She was a younger sister of King Louis IX of France (Saint Louis) and of Alfonso, Count of Poitiers, and an older sister of King Charles I of Sicily. In 1256, she founded the nunnery of Longchamp in part of the Forest of Rouvray (now called the Bois de Boulogne), west of Paris. Isabelle consecrated her virginity and her entire life to God alone. She is honored as a saint by the Franciscan Order. Her feast day is 26 February.
Early life
Born in March 1225, Isabelle was daughter of Louis VIII of France and Blanche of Castile. Her father died when she was two years old, and it was her mother, Blanche, who oversaw her education. Isabelle could read both Latin and the vernacular, and enjoyed tales of chivalry as well as devotional texts. While pursuing the traditional feminine interests such as embroidery, she took special pleasure in working on priestly vestments. As a child, she requested spiritual direction and became even more devoted to the Lord under the guidance of the Franciscans.
By virtue of the Treaty of Vendôme in March 1227, Isabelle was betrothed to Hugh, eldest son and heir of Hugh X of Lusignan, with the marriage contract being signed on June 1230; however, she refused to celebrate the formal wedding due to her fixed determination to remain a virgin, although she never became a nun. Later, she refused the hand of Conrad IV of Germany, son of Frederick II, Holy Roman Emperor, although pressed to accept by everyone, even by Innocent IV.
By the papal bull of 26 May 1254, Pope Innocent IV allowed her to retain some Franciscan friars as her special confessors. She was even more devoted to the Franciscan Order than was her royal brother.
Longchamp Abbey
thumb|left|Saint Louis laying the first stone of the Longchamp Abbey with Blessed Isabella of France and Queen Marguerite of Provence. Stained glass window of the Saint-Louis chapel of the Franciscans in Paris.
As Isabelle wished to found a community of Sorores minores (Sisters minor), her brother King Louis began in 1255 to acquire the necessary land in the Forest of Rouvray, not far from the Seine, west of Paris. On 10 June 1256, the first stone of the monastic church was laid. Pope Alexander IV gave his sanction on 2 February 1259 to the new Rule, which was composed especially for this monastery by Isabelle along with a team of Franciscan university masters including Bonaventure. The community was allowed to hold property. The monastery was named the Convent of the Humility of the Blessed Virgin. In the Rule the nuns were called the Sisters of the Humble Order of Servants of the Most Blessed Virgin Mary. The nuns were subject to the Friars Minor. Some of the first nuns came from the Poor Clare monastery in Reims. A revised version of the Rule was approved by Pope Urban IV on 27 July 1263, which granted the preferred name of Sorores minores inclusae, or Enclosed Sisters minor, for the nuns of Longchamp.
|6= 6. Alfonso VIII of Castile
|9= 9. Adèle of Champagne
|13= 13. Blanca of Navarre
|15= 15. Eleanor of Aquitaine