In the time of Saint Jerome, the Christian tradition had crossed the threshold of its second major syncretic transformation. This was not a theological, or a philosophical transformation. This was not a liturgical or ritual transformation, though it should be noted that syncretic transformations in each of those spheres was ongoing and continuous.
The second great syncretic movement was the transformation of the Church, founded on the teachings of Jesus of Nazareth, into the imperial Church of the Roman Empire.
When Saint Constantine, the first Christian emperor achieved his decisive victory over the armies of his enemies in his quest for control of the Roman Empire, he did it in the name of Jesus Christ, and what it meant to live the Christian life was changed forever.
The battle of the Milvian Bridge (28 October, 312 CE) was an epoch defining event.
The transformation of the Church, from the Church of Jesus, to the Church of Rome was not sudden. The emperor, Saint Constantine did not snap his fingers and make it so. It had been happening slowly over the course of generations, and centuries.
Since the time of Jesus, from one generation to the next the changes were gradual. From the beginning of the 1st century in the common era, to the beginning of the 4th century the change was also extreme.
Jesus of Nazareth, murdered by the Romans, executed for treason and sedition, murdered for preaching on the necessity of love, and mercy, and justice, became Jesus the Christ, a godling who brings victory in battle, and the cornerstone of the imperial government.
After the conversion of the Church, the range of vocations that qualified as “Christian” had drastically expanded. The act of filling these new roles: Christian emperor, Christian consul, Christian governor and Christian warrior is what constituted the new phase of syncretization in the Christian tradition according to the cultural norms of imperial society.
Bishops went from being the shepherds of a persecuted minority to being judges wielding authority in ecclesiastical courts, responsible for the prosecution of heresy, holding lands and titles, levying taxes and raising armies.
Bishops and priests went from being promoted by the members of their own community, to being appointed by the state.