POSSIDIUS, SAINT: Biographer of Augustine; d. after 437. Nothing is known of his life until 390 or 391, except that he was from northern Africa and was a pupil of Augustine and his intimate friend for forty years. In 397 he seems to have been consecrated bishop of Calama in Numidia, and he continually cooperated with Augustine in the struggle against paganism and in the war upon the heretics of the period, Arians, Manicheans, Donatists, Priscillianists, and Pelagians (see AUGUSTINE, SAINT, OF HIPPO). The extirpation of the heretics, especially the Pelagians, was doubtless due to the synodal activity of Augustine and Possidius. Between 394 and 424 Augustine summoned twenty synods mostly at Carthage; and while the signature of the bishop of Calama can scarcely be proved, his energy at one of the Carthaginian synods against the Pelagians won the praise of Innocent I. in his Inter cœteras Romanœ of Jan. 27, 417 (MPL, xxxiii. 783). In 429 northern Africa was ravaged by the vandals of Geiserich, and on the destruction of Calama Possidius fled to Hippo, where he was present at the death of Augustine on Aug. 28, 430. According to Prosper of Aquitane, Possidius and other bishops were expelled from Africa in 437 by Geiserich. Henceforth Possidius vanishes from history, and neither the place nor the date of his death is known, though apparently he lived to an advanced age. In the Roman Catholic calendar his day is May 17.

Shortly after 430 Possidius wrote his Vita Augustini (ed. J. Salinas, Augsburg, 1764; MPL, xxxii. 33-66), a work at once enthusiastic, modest, and reliable. He also made the first collection of the numerous writings of Augustine under the title Indiculus librorum, tractatuum et epistolarum sancti Augustini Hipponensis episcopi (MPL, xlvi. 5 sqq.), thus doing a valuable service for the earliest textual transmission of his teacher's works.