24. In the fourth century, given the new politico-social situation of the Church, the question of the relationship between liturgy and popular piety begins to be raised consciously in terms of adaptation and inculturation rather than solely in terms of spontaneous convergence.
A standard diagnosis, perhaps, but it seems to ignore possible influence from the mystery religions of the post-apostolic centuries. How much did paganism contribute to early Christianity. I don’t think we really know. But if history scholars are reading this, feel free to give some information on this point.
The local Churches, guided by clear pastoral and evangelizing principles, did not hesitate to absorb into the Liturgy certain purified solemn and festive cultic elements deriving from the pagan world. These were regarded as capable of moving the minds and imaginations of the people who felt drawn towards them. Such forms, now placed at the service of the mystery of worship, were seen as neither contrary to the Gospel nor to the purity of true Christian worship. Rather, there was a realization that only in the worship of Christ, true God and true Savior, could many cultic expressions, previously attributed to false gods and false saviors, become true cultic expressions, even though these had derived from (humankind’s) deepest religious sense.
If non-Christian influence is a question before 313, it certainly is well-documented afterward.
The full document, the Directory on Popular Piety and the Liturgy, is online at the Vatican site.