Gregorius (12) Baeticus , St., bp. of Eliberi, Elvira, or Granada, c. 357–384; first mentioned as resisting the famous Hosius of Cordova, when under the persecution of Constantius Hosius gave way so far as to admit Arian bishops to communion with him. This must have been in or before A.D. 357, the year of Hosius's death. At the council of Ariminum Gregorius was one of the few bishops who adhered to the creed of Nicaea, and refused to hold communion with the Arian Valens, Ursacius, and their followers. Our authority for this is a letter to Gregorius by Eusebius of Vercellae from his exile in the Thebaid (printed among the works of St. Hilary of Poitiers, ii. 700, in Migne, Patr. Lat. x. 713). Eusebius there acknowledges letters he had received from Gregorius, giving an account of his conduct, and commends him highly for having acted as became a bishop. Gams, however ( Kirchengesch. ii. 256–259, 279–282), maintains that Gregorius was one of the bishops who fell into heresy at Ariminum, and further identifies him with the Gregorius in the deputation sent by the council to Constantius and headed by Restitutus of Carthage, who assented to and subscribed an Arian formula of belief at Nice, in Thrace, Oct. 10, 359, and held communion with the Arian leaders, Valens, Ursacius, and others (St. Hilary of Poitiers, ex Opere Historico Fragmentum 8, in Migne, Patr. Lat. x. 702).
Gregorius is generally supposed to have been one of the leaders of the schism originated by Lucifer of Cagliari. This theory is supported by the terms of praise applied to him by the Luciferians Faustinus and Marcellus in their Libellus Precum ad Imperatores (c. 9, 10, 20, 25, 27, in Migne, Patr. Lat. xiii. 89, 90, 97, 100, 102); and also by the way St. Jerome, in his Chronicle under the date 374= a.d. 370 (in Migne, Patr. Lat. xxvii. 695), couples him with Lucifer of Cagliari, saying that the latter with Gregorius a Spanish, and Philo a Libyan, bishop, "nunquam se Arianae miscuit pravitati." Florez, however ( Esp. Sagr. xii. 121), maintains that no certain proof of this theory exists. Gams, on the other hand ( op. cit. ii. 310–314), maintains that even before the death of Lucifer, Gregorius was the recognized head of the sect. On the authority of the Libellus Precum , c. 25, he considers that Gregorius, after Lucifer's return from exile in 362, visited him in Sardinia; and he identifies with Gregorius the bishop mentioned in c. 63 as at Rome under the assumed name of Taorgius, and as having consecrated one Ephesius as bp. of the Luciferians there, an event which he dates between 366 and 371. From the Libellus Precum and the Rescript of Theodosius in reply addressed to Cynegius, Gregorius was apparently alive in 384. In none of the above passages is his see mentioned, as he is called only episcopus Hispaniarum or Hispaniensis, but it is supplied by St. Jerome, de Vir. Illust. c. 105 (Hieron. Op. ii. 937, in Migne, Patr. Lat. xxiii. 703) Opinions have been much divided as to the book de Fide , attributed to him by Jerome. The Bollandists (Acta SS. Ap 3:270
) say "etiamnum latet." It was formerly supposed to be the de Trinitate now ascribed to Faustinus. Gams (p. 314) thinks that this, though really written by Faustinus, is the work to which St. Jerome alludes.
The materials for a Life of Gregorius are thus scanty, the Libellus Precum being of very doubtful authority, and widely different estimates have been formed of him. But the two charges of Arianism and Luciferianism seem mutually destructive.