Hierarch
Hierarch Leander of Seville
ок. 534 — †ок. 600/601
Hierarch Leander of Seville — Archbishop of Seville, elder brother of St. Isidore of Seville (his successor on the see), who contributed to the conversion of the Visigothic kingdom from Arianism to Nicene Christianity: he converted, while in exile, the prince Hermenegild (later a martyr), and later presided over the Third Council of Toledo of 589, which officially established the Nicene confession of faith in Spain.
Hierarch Leander was born around 534 in Cartagena (southeastern Spain), into a distinguished Hispano-Roman family of the comes Severianus. After the death of his parents he raised his younger siblings — all later also numbered among the saints: Isidore (his successor on the Seville see, the era's great encyclopedist), Fulgentius (Bishop of Écija), and Florentina (abbess directing many women's communities).
He took monastic vows, then was consecrated Bishop (Archbishop) of Seville in 578/579. He founded a renowned theological school in Seville and became the chief opponent of Arianism in Visigothic Spain. Through his friendship with Princess Ingunda, he helped convert her husband, Prince Hermenegild, son of the Arian King Leovigild, from Arianism to Nicene Christianity (c. 579); Hermenegild was later executed by his own father for this conversion and is venerated as a martyr.
For his activity he was sent by Leovigild into exile in Constantinople (c. 579-582), where he formed a close friendship with the papal legate Pelagius — the future Pope Gregory the Dialogist (the Great), who later sent Leander the archiepiscopal pallium.
After Leovigild's death, his other son, King Reccared, embraced Nicene Christianity; St. Leander presided over the Third Council of Toledo (589), at which the Visigothic kingdom officially renounced Arianism in favor of the Nicene confession — the council also mandated recitation of the Creed at the Sunday liturgy. He composed an early form of the Hispano-Mozarabic liturgical rite, later refined by his brother Isidore; he wrote "Against the Arians" and a "Rule for Virgins" (addressed to his sister Florentina).
He mentored his younger brother Isidore, who inherited his see. He reposed around 600-601.
His feast is kept on November 1/14 (per the Lives of St. Dimitry of Rostov, together with Martyr Hermenegild); other traditions also give the dates February 27 and March 13.
IMPORTANT CORRECTION: category righteous→hierarch — Leander was Archbishop of Seville, already reflected in the stub's own text ("hierarch"), which contradicted the stated category.