Bishop of Bordeaux
Little is known of the origins of Saint Delphinus; it is after his elevation to the episcopate that he became famous among the bishops of his time as a vigilant protector of the truth. We have written evidence, however, that his piety and learning made him so celebrated that the saintliest bishops of the Church were honored to be his friends and to correspond with him.
He was present at the Council of Saragossa in 380, at which the Priscillian heretics were condemned. Later he assembled a Council in Bordeaux, his episcopal city, which the heretics had entered and where they were working havoc; this assembly condemned once again the same propagators of error. The bishop's force and preaching so reduced their influence that they abandoned the region entirely and fled to Italy.
Saint Delphinus baptized Saint Paulinus, later Bishop of Nola, in 388, and inspired in him the desire to live a life of perfection. He, in several letters, speaks of Saint Delphinus as his father and his master. Saint Delphinus died on the 24th of December, at the beginning of the fifth century.
Les Petits Bollandistes: Vies des Saints, by Msgr. Paul Guérin (Bloud et Barral: Paris, 1882), Vol. 14