Agathonicus was a 3rd-century resident of Nicomedia who traveled to Greece to spread Christian teachings. During the persecutions ordered by Emperor Maximian, he and several companions, including Zoticus, Princeps, and Theoprepius, were targeted by the imperial governor. After being apprehended, the group was moved toward Byzantium, facing severe mistreatment and death along the way. Ultimately, the remaining survivors were taken to Selymbria in Thrace, where they were executed by beheading.
Life and death
While preaching in Greece, Agathonicus faced intense opposition from imperial authorities. His followers suffered various fates, including crucifixion, while he and his companions were transported through Chalcedon. Many of his associates perished from exhaustion or abuse during this journey. The persecution concluded in Selymbria, where the survivors were tortured before being executed by the Greek Emperor.
Veneration
He is recognized as a saint within both the Catholic and Eastern Orthodox traditions. The Catholic Church observes his feast day on August 21, while the Eastern Orthodox Church commemorates him on August 22.