20,000 Martyrs of Nicomedia

The 20,000 Martyrs of Nicomedia refers to a period of persecution in Nicomedia by the Emperors Diocletian and Maximian in the early fourth century. According to various martyrology and menologion, the persecution included the burning of a church that held numerous Christians on Christmas Day. Roman martyrology reports four groups of martyrs from that time. While the number 20,000 may be apocryphal, the martyrs of Nicomedia continue to be honored with feast days.

They are commemorated on the 28 December in the Eastern Orthodox Church, and by the Byzantine Catholic and Latin Rite Catholic Churches.