This Dialogue was written about 379, seven years after the death of Lucifer, and very soon after Jerome's return from his hermit life in the desert of Chalcis. Though he received ordination from Paulinus, who had been consecrated by Lucifer, he had no sympathy with Lucifer's narrower views, as he shows plainly in this Dialogue. Lucifer, who was bishop of Cagliari in Sardinia, first came into prominent notice about a.d. 354, when great efforts were being made to procure a condemnation of S. Athanasius by the Western bishops. He energetically took up the cause of the saint, and at his own request was sent by Liberius, bishop of Rome, in company with the priest Pancratius and the deacon Hilarius, on a mission to the Emperor Constantius. The emperor granted a Council, which met at Milan in a.d. 354. Lucifer distinguished himself by resisting a proposition to condemn Athanasius, and did not hesitate to oppose the emperor with much violence. In consequence of this he was sent into exile from a.d. 355 to a.d. 361, the greater portion of which time was spent at Eleutheropolis in Palestine, though he afterwards removed to the Thebaid. It was at this time that his polemical writings appeared, the tone and temper of which is indicated by the mere titles De Regibus Apostaticis (of Apostate Kings), De non Conveniendo cum Hæreticis, etc. (of not holding communion with heretics). On the death of Constantius in 361, Julian permitted the exiled bishops to return; but Lucifer instead of going to Alexandria where a Council was to be held under the presidency of Athanasius for the healing of a schism in the Catholic party at Antioch (some of which held to Meletius, while others followed Eustathius), preferred to go straight to Antioch. There he ordained Paulinus, the leader of the latter section, as bishop of the Church. Eusebius of Vercellæ; soon arrived with the synodal letters of the Council of Alexandria, but, finding himself thus anticipated, and shrinking from a collision with his friend, he retired immediately. Lucifer stayed, and "declared that he would not hold communion with Eusebius or any who adopted the moderate policy of the Alexandrian Council. By this Council it had been determined that actual Arians, if they renounced their heresy, should be pardoned, but not invested with ecclesiastical functions; and that those bishops who had merely consented to Arianism should remain undisturbed. It was this latter concession which offended Lucifer, and he became henceforth the champion of the principle that no one who had yielded to any compromise whatever with Arianism should be allowed to hold an ecclesiastical office." He was thus brought into antagonism with Athanasius himself, who, it has been seen, presided at Alexandria. Eventually he returned to his see in Sardinia where, according to Jerome's Chronicle, he died in 371. Luciferianism became extinct in the beginning of the following century, if not earlier. It hardly appears to have been formed into a separate organization, though an appeal was made to the emperor by some Luciferian presbyters about the year 384, and both Ambrose and Augustine speak of him as having fallen into the schism.