February 1274-August 19, 1297

He was a cadet of the royal French house of Anjou who was made a Catholic bishop. The California mission and city of San Luis Obispo, California, is named after him.

He was born in Brignoles, Provence, the second son of Charles of Anjou "the Lame", who was appointed King of Naples, by the Papacy. That made the boy a nephew of St Louis IX of France and of Mary of Hungary (her great-aunt being Saint Elizabeth of Hungary). When his father was made prisoner in Italy, during the war with King Pedro III of Aragon that followed the Sicilian Vespers, he obtained his own freedom by giving over his three sons as hostages. The boys were taken to Barcelona, where they were placed under the care of Franciscan friars for their education and held for seven years. Though still held in captivity, Louis was made archbishop of Lyon as soon as he reached his majority. When his older brother died in 1295, Louis also became heir to his father's secular titles; however, when he was freed that same year, Louis went to Rome and gave up all claims to his royal inheritance in favor of his brother Robert of Anjou and announced that instead he would take the Franciscan vows of poverty, chastity, and obedience.

On February 5, 1297 as he took the Franciscan vows, Louis was also consecrated Bishop of Toulouse, where his uncle, Alphonse of Toulouse had until recently been Count, but had died in 1271 leaving no heir. In this ambivalently dynastic and ecclesiastical position, in a territory between Provence and Aquitaine that was essential to Angevin interests, despite the princely standing that had won him this important appointment at the age of about 22, Louis rapidly gained a reputation for serving the poor, feeding the hungry, and ignoring his own needs. After just six months, however, apparently exhausted by his labors, he abandoned the position of Bishop. Six months later, at age 23, he died of a fever, possibly typhoid, at Brignoles.

Procedures for his canonization were quickly urged. His case was promoted by Pope Clement V in 1307, and he was canonized by John XXII on April 7, 1317. The Franciscans kept his day in their calendar and removed his relics in 1423 to Valencia, where he was made patron Saint. It was thus that a Spanish Franciscan mission in Alta California came to be consecrated to San Luis Obispo.

He can be recognized in some iconography as a boy bishop, often with a discarded crown by his feet.