He did, but I'm probably exclusively talking about Greco-Roman Pagan traditions, as Judaism and possibly Zoroastrianism had begun having big impacts on them. I couldn't point you to any sources, but it appears monotheism, not any particular religion associated therewith prior to Christianity, was already on the rise in these areas. It would be another reason why Christianity was so popular so early. Paganism came with a lot of built-in social inequalities in Greece and Rome, which I can imagine many wanted abolished - and these are the groups we see turning to Christianity first: slaves, women, outcasts etc.