AMBROSIUS, DEACON. — Disciple and correspondent of Origen, confessor of the faith. Of noble and wealthy family, perhaps Alexandrian, he was a deacon, though married with children. Having been induced to embrace a Gnostic sect, he was converted around 212 by Origen. From then on he remained faithful to his master and not only encouraged him in every way to compose various works, but also provided him with the means to write them and to deepen his studies. During the persecution under Maximinus Thrax, A. was imprisoned and maltreated, but was eventually freed. He died not long after, shortly before Origen himself.
Among the numerous works dedicated to him by Origen, particular note should be made of the Exhortatio ad martyrium which he sent him while he was in prison (PG 11, 563-638), and the Contra Celsum composed at A.’s urging.