The Forty Martyrs of Sebaste were a group of Roman soldiers in the Legio XII Fulminata (Armed with Lightning) whose martyrdom in 320 for the Christian faith is recounted in traditional martyrologies. They were killed near the city of Sebaste in Lesser Armenia, victims of the persecutions of Licinius. The earliest account of their existence and martyrdom is given by Bishop Basil of Caesarea (370–379) but the Feast of the Forty Martyrs is older than Basil himself, who eulogised them only fifty or sixty years after their deaths.
According to Antonio Borrelli, their names were: Aetius, Eutychius, Cyrius, Theophilus, Sisinnius, Smaragdus, Candidus, Aggia, Gaius, Cudio, Heraclius, John, Philotemon, Gorgonius, Cirillus, Severianus, Theodulus, Nicallus, Flavius, Xantius, Valerius, Aesychius, Eunoicus, Domitian, Domninus, Helianus, Leontius (Theoctistus), Valens, Acacius, Alexander, Vicratius (Vibianus), Priscus, Sacerdos, Ecdicius, Athanasius, Lisimachus, Claudius, Ile, Melito and Eutychus (Aglaius).
They are venerated in Eastern Orthodox Church, Oriental Orthodox Church, Eastern Catholic Churches, Roman Catholic Church and their Feast is commemorated on March 9 (East) and March 10 (West).