Interesting. I've never thought of it that way. I do remember singing Age of Aquarius
on the bus to CYO Camp.
When I think about the origins of Christianity I think about the names of the days of the week. Not a whole lot of Christianity to be found there.
For Christmas we bring a tree into our homes, decorate it with pretty lights and shiny things, then place gifts under it. Why? Because spruced up conifers have everything to do with the birth of Jesus and nothing to do with Celtic tree worship.
The astrology theories make sense. Perhaps I never thought of that because the word "astrology" makes me a bit queasy. That comes from reading a lot of Heinlein who missed no opportunity to mock astrology.