Patriarch of Antioch (465-488). He accompanied the future Emperor Zeno, the son-in-law of Leo, to Antioch, incited the people against Martyrius the Nestorian patriarch, and, upon the latter's resignation, installed on the See of Antioch in 468. He gained the favor of the Orthodox people in Antioch. Patriarch Peter at once declared himself openly against the Council of Chalcedon, and proved to the Trisagion the words "Who wast crucified for us," in the church because the Trisagion directed to the Son who crucified for the mankind. He anathematized those who declined to accept it, and he summoned a council at Antioch to give synodical authority to this clause.

In 471 he was deposed by the Emperor, but he again come back to the see in 476 to be deposed a second time and banished in 478. The Emperor Basilicus reinstated him in 485 and he held the See until his death.

The deposed Martyrius went to Constantinople to complain to the emperor Leo, by whom, through the influence of the patriarch Gennadius, he was courteously received; and his restoration was decreed. But despite the imperial authority, Peter's personal influence, supported by the favour of Zeno, was so great in Antioch that Martyrius's position was rendered intolerable and he soon left Antioch. Leo was naturally indignant at this audacious disregard of his commands, and he dispatched an imperial decree for the deposition of Peter and his banishment to the Oasis.

The Emperor Leo installed Julian the Chalcedonian, Patriarch in his place (471), holding the see until Peter's third restoration by Basiliscus in 475/6, and with him many bishops returned from their exile to their sees. During the short reign of the Basiliscus (Oct. 475-June 477) held a Synod (475/6) in Constantinople which fife hundred bishops attend and anathematized the decrees of Chalcedon, Basiliscus declared for the Orthodox bishops, recalled Timothy Aelurus, Patriarch of Alexandria, from exile. Peter gladly complied, and was rewarded by a third restoration to the see of Antioch, 476. Julian was deposed, dying not long after.

Once Peter comes back to the patriarchal throne, he was not slow to stretch its privileges to the widest extent, ordaining bishops and metropolitans for all Syria. The fall of Basiliscus brought the destruction of all who had supported him (Basiliscus) and been promoted by him, and Peter was one of the first to fall because Zeno thought that Peter colluded with Basiliscus against him. Upon deposition of the Patriarch Peter, the Orthodox bishops installed John bishop of Ephamia Patriarch of Antioch, 476-478 (was Orthodox), Emperor Zeno deposed him and replaced him with Stephanus (Chalcednian), 478-481, been killed, and then Callandion 481-482. In purpose to render the peace in the church Zeno in 482, held the Synod in Constantinople and issued the famous Henoticon which was accepted Alexandrian Patriarch Peter Mangus and that of Constantinople Acacius. Callandion of Antioch was Chalcedonian, refused it, deposed by Emperor Zeno and  for the last time Peter was replaced on his throne, and he also accepted the Henoticon of Zeno. He at once resumed his started to put the church in order, and consecrated the famous Xenaias (Philoxenus) to the see of Hierapolis 485 or Mabbogh (Manbege).

Peter retained, however, the patriarchate at Antioch till his end of his agony in 488. One of his last acts was to enforce the (Canon of the Faith) to be recited in the church of Antioch at the Divine Liturgy.