Nicomedia
City of Bithynia on the Sea of Marmara and the residence of Diocletian. The Great Persecution began here in 303, Galerius’s edict of toleration was posted here in 311, and Constantine was baptised and died nearby in 337.
Nicomedia stood at the head of a gulf of the Sea of Marmara, in the province of Bithynia. Diocletian kept his court there. Lactantius, who taught in the city, says that its church stood on high ground in sight of the palace and was pulled down in a few hours on 23 February 303 (Lactantius, Deaths of the Persecutors 12). Diocletian laid down his office on a hill three miles outside the walls (Lactantius, Deaths of the Persecutors 19). The edict by which Galerius ended the persecution was posted in the city on 30 April 311 (Lactantius, Deaths of the Persecutors 35), and two years later Licinius published there the letter granting freedom of worship (Lactantius, Deaths of the Persecutors 48). In 337 Constantine was baptised in its suburbs and died there (Eusebius, Life of Constantine 4.61–64).
What happened here
- AD 303 to AD 311, firm dateThe Great Persecution under Diocletian
In February 303 Diocletian orders churches demolished and Scriptures burned. Further edicts imprison the clergy and require everyone to sacrifice. The persecution is brief in the West and lasts eight years in the East.
- 30 April AD 311, firm dateGalerius Grants Toleration
The emperor Galerius, mortally ill, issues an edict that ends the Great Persecution in his territories. It allows Christians to exist again and to rebuild their meeting places, and asks them to pray for the emperors and the state.
- AD 313, firm dateThe Edict of Milan
Constantine and Licinius agree at Milan that Christians and everyone else may worship as they choose. The text that survives is a letter Licinius had posted at Nicomedia in June 313, which also orders confiscated church property returned.