Life and Confession
Agathonicus lived in Nicomedia (modern İzmit in present-day Turkey), then a major city of the Roman Empire in Asia Minor. According to the tradition he came of an illustrious family and was well versed in Scripture, which he used to teach and to convert many from paganism to the Christian faith. He is described as a prominent figure, the OCA life calling him a leader within the Senate.
The Wikipedia account adds that while living in Greece he taught the Greeks about Christianity, before the persecution overtook him and his companions.
Persecution and Martyrdom
The persecution was carried out under the authority of Emperor Maximian (reigned 284–305). According to the OCA life, a Roman official named Comitus Eutolmius directed it: he crucified followers of the Christian Zoticus in the Pontine region after they refused to worship idols. Eutolmius then arrested Agathonicus together with Theoprepius, Acindynus, and Severian in Nicomedia.
After torturing them, Eutolmius ordered the prisoners transported toward Thrace for trial before the emperor. During the journey near Potama, three of the martyrs — Zoticus, Theoprepius, and Acindynus — died of wounds inflicted by torture that left them unable to travel further. Severian was put to death at Chalcedon. Agathonicus and the remaining companions were beheaded by the sword at Selymbria by order of the emperor.
The Wikipedia account gives a parallel narrative: Zoticus was seized at Carpe and his followers crucified, after which Zoticus was sent to Nicomedia; from there Agathonicus and his companions were taken toward Byzantium, with many dying of exhaustion and abuse along the way and others killed at Chalcedon, until the survivors were beheaded at Selymbria in Thrace after being tortured before the emperor.
Relics & Shrines
According to the OCA life, the relics of Agathonicus were later kept in a church bearing his name in Constantinople. A Russian pilgrim named Anthony is recorded as having venerated the relics there around the year 1200.
Veneration and Legacy
In the fourteenth century, Archbishop Philotheus of Selymbria — the place of Agathonicus's beheading — composed an encomium in honor of the martyr.
Agathonicus is venerated in both the Eastern Orthodox and Western traditions, commemorated on August 22 in the Orthodox Church and on August 21 in the Catholic Church.
