The Edict of Milan (Latin: Edictum Mediolanense; Greek: Διάταγμα τῶν Μεδιολάνων, Diatagma tōn Mediolanōn) was the February, AD 313 agreement to treat Christians benevolently within the Roman Empire.[1] Western Roman Emperor Constantine I and Emperor Licinius, who controlled the Balkans, met in Mediolanum (modern-day Milan) and, among other things, agreed to change policies towards Christians[1] following the edict of toleration issued by Emperor Galerius two years earlier in Serdica. The Edict of Milan gave Christianity legal status and a reprieve from persecution but did not make it the state church of the Roman Empire,[2] which occurred in AD 380 with the Edict of Thessalonica,[3] when Nicene Christianity received normative status.[4][5]
The version found in Lactantius is not in the form of an edict.[7] It is a letter from Licinius to the governors of the provinces in the Eastern Empire that he had just conquered by defeating Maximinus[9] later that same year and issued in Nicomedia.[1][10]
^The Cambridge History of Christianity. Cambridge University Press. Quote: "Christianity did not become the official religion of the empire under Constantine, as is often mistakenly claimed..."
^World Encyclopaedia of Interfaith Studies: World religions. Jnanada Prakashan. 2009. ISBN978-81-7139-280-3. In the most common sense, "mainstream" refers to Nicene Christianity, or rather the traditions which continue to claim adherence to the Nicene Creed.
^As David Potter states in his 2013 book Constantine the Emperor, "What is significant is that the document, once wrongly known as the Edict of Milan (there was never such a thing) and attributed to Constantine, is the product of a pagan emperor who had decided that Constantine's approach to the "Christian question" was correct. Although the 'Edict of Milan' is really a letter of Licinius to the governors of the eastern provinces, it still represents an important sea change in the direction of imperial policy." Potter p. 149