Alypius St., of Tagaste, in Numidia, was some years younger than Augustine, to whom he was strongly attached. From Carthage, whither he followed Augustine, he went to Rome to study the law, and there obtained a place in the imperial treasury. This charge he gave up in order to follow Augustine to Milan. Both of them up to this time had been Manichaeans, and both were at this time converted to the Catholic faith, and baptized in the church of St. Ambrose on Easter-eve, A.D. 387. Upon their return to Africa they withdrew into a solitude near Tagaste; but when Augustine was ordained a priest of the church of Hippo, he drew Alypius from his solitude to take charge of the monastery which he had just built in Hippo. After this Alypius visited the Holy Land, and upon his return in 394 was elected bishop of Tagaste. In 403 he was present at a council held at Carthage in which the Donatists were invited to a conference, but refused; and in 411 he was named, with six others, to represent the Catholics in the celebrated conference between the Catholics and Donatists which the Emperor Honorius enjoined. It is believed that he was with Augustine at Hippo at the time of his death in 430, and it is uncertain how long he survived him. The Roman Martyrology commemorates him on the 15th of August. — S. August. Confess. lib. 6; Ep. 22, etc.; S. Jerome, Ep. 81; Baillet, Aug. 15; Butler, Lives of Saints, 3, 375.