(13 Mar. 483–1 Mar. 492)
A Roman of aristocratic family, he was son of a priest, himself a deacon and a widower with at least two children (from one of whom Gregory I was descended). A decisive part in his election was played, at the request of his predecessor, by Basilius, praetorian prefect of Odoacer, king of Italy (476–93), who also had an ecclesiastical law promulgated forbidding the alienation of church property by the popes on pain of anathema. Because of the posthumous inclusion of Antipope Felix in the list of legitimate popes as Felix II, he was improperly given the style Felix III.
Felix, who relied heavily on his archdeacon (and successor) Gelasius, was from the start closely involved with the east. News had just reached Rome of the Henoticon, a compromise doctrinal statement designed to appease the monophysite opposition to the ‘two natures’ Christology approved at Chalcedon (451) which Emperor Zeno (474–91) had published in 482. A monophysite, Peter Mongos, had been installed as bishop of Alexandria, and his orthodox but extruded predecessor, John Talaia, was in Rome full of bitter complaints. Felix dispatched an embassy to Constantinople with letters to emperor and patriarch. Now that there was no emperor in the west he announced his election to the emperor in the east (the first instance of a pope so doing), sought Zeno's aid for Catholics in north Africa persecuted by the Arian Vandals, but chiefly demanded the deposition of Peter Mongos and the maintenance of the Chalcedonian Christology. A first letter to Patriarch Acacius reproached him for supporting Mongos and the Henoticon, but a subsequent one summoned him to Rome to answer the charges of John Talaia. The embassy proved a fiasco: the legates let themselves be imposed upon and failed to protest when Acacius included Mongos in the diptychs, i.e. the names of living and departed publicly prayed for at mass, thus giving the impression that Rome approved of him and the Henoticon. On their return the infuriated pope excommunicated both his legates and Acacius at a synod held on 28 July 484. He angrily warned the emperor not to interfere in matters which belonged to the church's bishops, and sent his sentence of excommunication on Acacius to Constantinople by a special messenger. Some overzealous orthodox monks in the city made it blatantly public by pinning it on to Acacius' vestments as he was celebrating mass.
Felix's sentence had no practical effect on Acacius, beyond provoking him to remove the pope's name from the diptychs, but it started the Acacian schism, which divided the churches of east and west for 35 years (484–519). Even some of Felix's supporters in Constantinople were dismayed, but reports of this, and of the replacement of the Chalcedonian bishop of Antioch by a monophysite, Peter the Fuller, only stiffened his attitude. He held a fresh synod (5 Oct. 485) which approved a letter confirming, for the benefit of the people of Constantinople, his excommunication of Acacius; he also deposed, without effect, the monophysite bishop of Antioch. In 488/9 an opportunity for healing the rift occurred when Odoacer, threatened by Theodoric the Ostrogoth, king of Italy (493–526), was seeking a political rapprochement with Zeno, but Felix's terms were complete submission by Acacius. Again, when Acacius died (28 Nov. 489) to be replaced—briefly—by Fravitas and hopes of reunion ran high in Constantinople, he refused to accept any overtures so long as Mongos occupied the see of Alexandria and his name and that of Acacius were recited in the diptychs. In 491, when Mongos (29 Oct. 490) and Zeno (9 Apr. 491) were both dead, the new patriarch Euphemius, an orthodox Chalcedonian alarmed at the accession of an emperor, Anastasius I (491–518), with monophysite leanings, wrote to Felix seeking the restoration of communion between the two churches; but while commending his orthodoxy the pope declined to make any move until Acacius' name was removed from the diptychs.