CONCERNING THE JEWISH NEW YEAR:
Rosh Hashanah 2017: The History of Rosh Hashanah Which Wasn't Always the 'New Year.' Much of today's traditions originated with Babylonian worship, and you have to read this to believe how a calf's head morphed into gefilte fish. (Elon Gilad, Haaretz).
There's lots of useful historical background here.
UPDATE: I've deleted a sentence that contained incorrect information. Sorry for the error.
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