How did the Greek mythology ways pass on to the Roman mythology ways.

Explanation:

I will start out by pointing out that the Romans have a significant amount of religion/mythology that has nothing to do with the Greeks.

1) Saturn, Quirinus, Janus, Dis Pater, Liber, and the Lares are all Italian gods without an equivalent from Greek culture. These gods were worshiped in Italy before the Greek influence crept in.

2) Romans have Gods from several other cultures: they incorporated the Anatolian goddess as “Magna Mater”, borrowed Isis and a number of Egyptian gods from Egypt.

3) The Greek Gods themselves are not all Greek. Apollo seems to have migrated into Greece from the Middle East, and in fact, there are many similar characters in Babylonian, Etruscan, and Egyptian mythology. Also, since Greece was not a unified country until very recently, there were a large number of Greek deities with similar identities and different names, as well as gods with the same name, but completely different portfolios (in some places, Venus was a goddess of war!)