LIBERIUS, pope from 352 to 366, the successor of Julius I., was consecrated according to the Catalogus Liberianus on the 22nd of May. His first recorded act was, after a synod had been held at Rome, to write to Constantius, then in quarters at Arles (353–354), asking that a council might be called at Aquileia with reference to the affairs of Athanasius; but his messenger Vincentius of Capua was compelled by the emperor at a conciliabulum held in Arles to subscribe against his will a condemnation of the orthodox patriarch of Alexandria. In 355 Liberius was one of the few who, along with Eusebius of Vercelli, Dionysius of Milan and Lucifer of Cagliari, refused to sign the condemnation of Athanasius, which had anew been imposed at Milan by imperial command upon all the Western bishops; the consequence was his relegation to Beroea in Thrace, Felix II. (antipope) being consecrated his successor by three “catascopi haud episcopi,” as Athanasius called them. At the end of an exile of more than two years he yielded so far as to subscribe a formula giving up the “homoousios,” to abandon Athanasius, and to accept the communion of his adversaries—a serious mistake, with which he has justly been reproached. This submission led the emperor to recall him from exile; but, as the Roman see was officially occupied by Felix, a year passed before Liberius was sent to Rome. It was the emperor’s intention that Liberius should govern the Church jointly with Felix, but on the arrival of Liberius, Felix was expelled by the Roman people. Neither Liberius nor Felix took part in the council of Rimini (359). After the death of the emperor Constantius in 361, Liberius annulled the decrees of that assembly, but, with the concurrence of SS. Athanasius and Hilarius, retained the bishops who had signed and then withdrawn their adherence. In 366 Liberius gave a favourable reception to a deputation of the Eastern episcopate, and admitted into his communion the more moderate of the old Arian party. He died on the 24th of September 366.
His biographers used to be perplexed by a letter purporting to be from Liberius, in the works of Hilary, in which he seems to write, in 352, that he had excommunicated Athanasius at the instance of the Oriental bishops; but the document is now held to be spurious. See Hefele, Conciliengesch. i. 648 seq. Three other letters, though contested by Hefele, seem to have been written by Liberius at the time of his submission to the emperor. (L. D.*)