This new study argues that the religious attitude of the Roman army was a crucial factor in the Christianization of the Roman world. Specifically, by the end of the third century, there was a significant Christian presence within the army which was ready to act in the interests of the faith. Conditions at this time were thus ripe for the coming to power of a Christian emperor: when Constantine converted to Christianity he could rely upon the enthusiastic support of his Christian soldiers. Constantine strengthened his Christian base by initiating policies which accelerated the Christianization...