Modulo some trivial semantics. The canonical nine muses didn't get sorted out from the Fates, Graces, Furies, Naiads, Dryads, and so on for a long time.
I've often wondered what level of belief people actually had in ancient deities. Were there people who honestly believed in the existence of all these gods in the same way that the Pope believes in his god? Or perhaps people believed in the major gods (Zeus etc) while being a bit iffier on the personified concepts in the same way that Christians nowadays might believe in God and Jesus but perhaps be a little iffy on the distinction between angels, archangels and seraphim?