Leander of Seville was the Bishop of Seville. He was instrumental in effecting the conversion of the Visigothic kings Hermengild and Reccared to Catholicism. His brother was the encyclopedist St. Isidore of Seville. Leander, Isidore and their siblings belonged to an elite family of Hispano-Roman stock of Carthago Nova. The family as a matter of course were staunch Catholics, as were most of the Romanized population; the Visigothic nobles and the kings were Arians.

The family moved to Seville around 554. The children's subsequent public careers reflect their distinguished origin: Leander and Isidore both became bishops of Seville, and their sister Florentina was an abbess who directed forty convents and one thousand nuns. The third brother, Fulgentius, was appointed Bishop of Écija. All four siblings are considered saints of the Roman Catholic Church and of the Orthodox Church.

Leander, enjoying an elite position in the secure surroundings of tolerated Catholic culture in Seville, became a Benedictine monk around 576, and then in 579 he was appointed bishop of Seville. In the meantime he founded a celebrated school, which soon became a center of Catholic learning. As bishop he had access to the Catholic Merovingian princess Ingunthis, who had come as a bride for the kingdom's heir, and he assisted her to convert her husband Hermenegild, the eldest son of Liuvigild, an act that cannot honestly be divorced from a political context. Leander defended the new convert even when he went to war with his father "against his father's cruel reprisals".

Leander introduced the recitation of the Nicene Creed at Mass, as a way to help reinforce the faith of his people against Arianism. In 589, he convoked the Third Council of Toledo, where Visigothic Hispania abjured Arianism. Leander delivered the triumphant closing sermon which his brother Isidore entitled Homilia de triumpho ecclesiae ob conversionem Gothorum ("a homily upon the triumph of the Church and the conversion of the Goths"). On his return from this council, Leander convened a synod in his metropolitan city of Seville (Conc. Hisp., I), and never afterwards ceased his efforts to consolidate the work of extirpating the remains of Arianism, in which his brother and successor St. Isidore was to follow him.

St.Leander died in the year 601. He was succeeded as bishop by his brother St. Isidore. He is considered a Doctor of the Church.

Other Saints of the Day
1. Saint Agnellus of Pisa
2. Saint Ansovinus
3. Saint Heldrad
4. Saint Kevoca
5. Saint Nicephorus