Ildefonsus was born December 8, 607, to an important Visigothic family in Toledo Spain, during the reign of Witteric. Civil wars were ongoing throughout the Visigothic kingdom during most of Ildefonsus’ life. His uncle Eugenius, who later became the Bishop of Toledo, taught Ildefonsus. He began his religious career around 632 when Bishop Eladius of Toledo ordained him as a deacon. Ildefonse did not follow his family’s wishes to become a priest, instead, he became a monk at the Agali monastery outside the city. While he was a monk, he founded and endowed a community of nuns.In 650 Ildefonsus was elected its abbot of Agali. While abbot, he attended two conferences of the Church on the Iberian peninsula. These were called the 8th and 9th Councils of Toledo. When his uncle Bishop Eugenius II died in 657, Ildefonsus was elected his successor as bishop of Toledo. King Recceswinth made him accept the position, as Ildefonsus later complained to his successor, Bishop Quiricus of Barcelona.
Cixila, Archbishop of Toledo, told the story once, that Ildephonsus was praying one day before the relics of Saint Leocadia when the martyr rose from her tomb and thanked him for the devotion he showed towards the Mother of God. It was reported that on December 18, 665 he experienced a vision of the Blessed Virgin when she appeared to him in person and presented him with a priestly vestment, to reward him for honoring her. As Bishop Ildefonsus and the congregation sang Marian hymns, light engulfed the church, causing most worshippers to flee. Ildefonsus stayed with a few deacons, saw Mary descend and sit in the priest’s chair. She praised Ildefonsus for his devotion and gave him a special chasuble. She told him to wear it only during Marian festivals.
Ildefonsus died after a decade as a Bishop on January 23, 667. He was buried at his basilica, Toledo’s Church of Santa Leocadia. Even during the Muslim occupation, when the basilica was converted into a mosque, the area where the vision occurred remained sacred and dedicated to the Virgin Mary.