The Edict is popularly thought to concern only Christianity. In fact the Edict expressly grants religious liberty not only to Christians, who had been the object of special persecution, but to all religions
The document is found in Lactantius' De Mortibus Persecutorum and in Eusebius of Caesarea's History of the Church with marked divergences between the two. Whether or not there was a formal 'Edict of Milan' is no longer really debated among scholars who generally reject the story as it has come down in church history.
The version found in Lactantius is not in the form of an edict. It is a letter from Licinius to the governors of the provinces in the Eastern Empire he had just conquered by defeating Maximinus later in the same year and issued in Nicomedia on June 13, 313.
Since the fall of the Severan dynasty in AD 235, rivals for the imperial throne had bid for support by either favoring or persecuting Christians. The previous Edict of Toleration by Galerius had been recently issued by the emperor Galerius from Serdica and was posted at Nicomedia on 30 April 311. By its provisions, the Christians, who had "followed such a caprice and had fallen into such a folly that they would not obey the institutes of antiquity," were granted an indulgence. Their confiscated property, however, was not restored until 313, when instructions were given for the Christians' meeting places and other properties to be returned and compensation paid by the state to the current owners.