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Protestant historians would typically argue that this is historically what the Christian church was before the Emperor Constantine legalized Christianity (see Early Christianity) and before the later setting up of the state church of the Roman Empire, and did not appear again until the appearance, within the Protestant Reformation, of groups such as the Calvinists and radical movements such as the Anabaptists.
Curiously enough Melanchthon's letter introducing Sozzini to Maximilian II invokes as an historic parallel the hospitable reception rendered by the Emperor Constantine to Athanasius when he fled from Egypt to Trèves.
312: Maxentius consulted the Sibylline Books in preparation for combat with Constantine, who had recently switched his allegiance from Apollo to Christ.