Saint Gerontius, Bishop of Italica, preached in Baetica, and without doubt must have left a pastor of its own to Seville.

It is certain that in 303, when Saints Justa and Rufina were martyred for refusing to adore a pagan idol, there was a Bishop of Seville named Sabinus, who assisted at the Council of Illiberis in 287.

The former of these contributed to the conversion of Saint Hermengild and Recared, and presided at the Third Council of Toledo in 589.

In addition to the cathedral chapter, another community of clerics was formed to sing the Divine Office in the Chapel Royal of Our Lady of the Kings (Nuestra Senora de los Reyes) about 1252.

In order to secure the liturgical orientation, when the mosque was converted into a cathedral its width was made the length of the new church; and it was divided into two parts, the lesser part, on the cast, being separated from the rest by a balustrade and grating, to form the chapel royal.