Episcopate during the Persecution
Peter became Archbishop of Alexandria around the year 300, succeeding Theonas. When the Diocletianic persecution began in 303 and intensified in the years that followed, he was forced into exile from the city. Rather than abandon his flock, he governed it at a distance: he maintained contact through letters, secretly visited Christians who had been imprisoned, conducted clandestine worship, and saw to the care of widows and orphans.
A pastoral controversy arose over how to treat the 'lapsed' — Christians who had compromised under torture by offering pagan sacrifice or surrendering the Scriptures. Peter favored a measured leniency that allowed for the lapsed to be restored through penance, and he came into conflict on this point with Meletius of Lycopolis, who demanded far stricter terms. Their disagreement, said to have begun while both were imprisoned, hardened into the Meletian schism. Peter's own teaching on the discipline of repentance was preserved in his 'Penitential Canons,' which the later Church held in high regard.
Conflict with Arius
Among the figures connected to the Meletian faction was the priest Arius, who denied the full divinity of Christ. Peter confronted him and, when Arius refused to correct his position, anathematized and excommunicated him from the Church. According to the tradition, Arius later sought reconciliation through intermediaries, but Peter rejected these appeals and would not absolve him. Peter thus opposed Arius before the controversy that would dominate the Council of Nicaea had fully unfolded.
Martyrdom
On the orders of the emperor Maximian, Peter was arrested in 311 and sentenced to death. By the traditional account, Christian crowds gathered at the prison in his defense, and Peter, seeking to spare his people from bloodshed, arranged for the soldiers to take him quietly. He was led beyond the city walls and beheaded at the very spot where, by tradition, the Evangelist Mark had earlier been martyred.
Because he was the last of the Alexandrian martyrs to die in the Diocletianic persecution, the Greek tradition gave him the title 'the seal and limit of the persecution,' commonly rendered 'the Seal of the Martyrs.' A tradition records the saying that as the Apostle Peter was first among the Apostles, so Peter of Alexandria was the last of the Alexandrian martyrs.
Veneration and Legacy
Peter is venerated as a hieromartyr by the Eastern Orthodox Church, and — as a saint of the undivided pre-Nicene Church — also by the Coptic Orthodox and Roman Catholic Churches. He is commemorated on November 25 in the Slavic tradition, with the Greek tradition observing him on November 24.
Beyond the 'Penitential Canons,' Peter was remembered as a theological authority: passages from his treatise 'On the Divinity (of Jesus Christ)' were cited at the later Councils of Ephesus and Chalcedon, a measure of the weight his orthodoxy carried in the Christological controversies that followed his death.
