Isabelle of France

Isabelle of France was born in March 1225, the daughter of King Louis VIII of France and Blanche of Castile. She was the sister of King Louis IX, later venerated as Saint Louis, and of Robert, Count of Artois; Alphonse, Count of Poitiers; and Charles of Anjou, later King of Sicily. After Louis VIII died in 1226 she was raised under the strong religious influence of her mother, who served as regent. Near-contemporary testimony, above all the life written later in the thirteenth century by Agnes of Harcourt, abbess of Longchamp, presents Isabelle as literate, including in Latin, and as given from youth to prayer, fasting, and care for the poor.

Although a Capetian princess, she refused marriage. The most politically important proposal would have joined her to Conrad, son of Emperor Frederick II. She insisted on remaining unmarried and consecrated to God. With the support of Louis IX she founded a monastery of Franciscan nuns, the Poor Clares, at Longchamp in the forest of Rouvray west of Paris, in the area later known as the Bois de Boulogne. Construction is generally placed in the mid-1250s. The house was dedicated to the Humility of the Blessed Virgin Mary. Pope Alexander IV approved a distinctive rule for the community in the late 1250s, somewhat milder than the strictest Poor Clare observance then in use.

Isabelle lived at Longchamp in retirement, humility, and charity. She did not serve as abbess. Medieval and modern accounts differ on whether she ever made a full canonical profession as a nun; she is most securely described as foundress and as a royal woman living in religious community rather than as a conventional abbess or choir nun. She was associated with personal austerity, devotion to the Eucharist and the Passion, and practical care for the sick and the poor.

She died at Longchamp on 23 February 1270, months before Louis IX died on crusade, and was buried in the abbey church. A local cult formed at her tomb and miracles were reported. Pope Leo X beatified her in 1521 and allowed a liturgical office in her honor at Longchamp; later grants spread her cult among Franciscans and in France. She was not put through a formal canonization process of the later type. Her feast is kept on 26 February. Longchamp Abbey was suppressed in the French Revolution and its buildings were demolished. The principal narrative sources remain Agnes of Harcourt's life, royal and papal documents for the foundation, and the later liturgical cult.