Apologists and, perhaps, a few believers dreamed that their religion might be politically favoured, but most Christians had experienced too many political nightmares to cherish such hopes. The emperor Diocletian’s persecution (303–11) had given no hint of what was in store. He was a convinced follower of traditional religions, one who made no momentous military plans without discovering the will of the gods. The pagan priests warned that his whole campaign against the Persians was endangered because they could not read the gods’ signs while there were Christians in the court. That such people were at court indicates their rise within Roman political and cultural circles; that they could be dismissed and persecuted shows how tenuous their positions were. All of them were expendable. Lactantius’ personal reflections tell us of the palace intrigue, but a Coptic martyrology speaks of high-ranking Christian families in Antioch, members of the city council and generals in the legions based outside the city, who were exiled and put to death in Egypt. These persons were both religiously and politically too strong to be left within Diocletian’s base of supplies and troops for eastern battles.

Constantine did not choose Christianity because it brought him a majority of those within his rule. The reasons for his inclusion of that faith in the 313 decision of Milan about religious toleration are multiple and ambiguous. His vision at the Milvian Bridge provided a view of the Christian god who gave him victory. Yet his killing members of his own family indicates that he did not understand much about the virtues demanded by his new faith. The ‘Edict of Milan’ concerned toleration, meaning only that Christians were now included among the authorised religions. Previous pagan emperors were somewhat curious about Christianity; some had persecuted it. But none of them had converted or had worked to make the religion officially sanctioned.