The idea of dying and being resurrected was taught by the mystery schools and others as the path to connecting to "god" or the mysteries, saw a great video on it but can't remember which, here's a few, I think it might have been Dark Journalist with Joseph P. Farrel:
https://www.youtube.com/results?search_query=resurrection+the+mystery+schools.
The initiate was actually brought to a state of physical death or very close by drugs and then taught by entities on the other side, then resurrected. The story of Christ's resurrection is a continuation of a long spiritual tradition.