Berossus was 3d century BC. The Septuagint had already been written and moreover Berossus was on Cos in the Aegean and under the patronage of the Ptolemaic kings of Alexandria - which closes the circle even more.
Since we have exactly zero evidence of any of the tales existing in written form prior to the Greek version it seems reasonable that they were oral traditions ( common in ancient religion ) until the damn Greeks came along with their new-fangled WRITING!!!!
Since we have exactly zero evidence of any of the tales existing in written form prior to the Greek version it seems reasonable that they were oral traditions ( common in ancient religion ) until the damn Greeks came along with their new-fangled WRITING!!!!