Everyone knows that the Romans adopted the pantheon of Hellenistic gods as their own, and renamed them: Zeus, Hera, Aphrodite, Hermes, (etc.) became Jupiter, Juno, Venus, Mercury, (etc.) respectively. All except Apollo, who was referred to as Apollo by the Romans as well as the Greeks. Why did they make such an exception for Apollo? In fact, why did the Romans feel the need to change the names of the greek gods at all?
Why did the Romans adopt all these new gods in the first place? Didn’t they have a religion of their own? What was that earlier religion like, and were any old customs retained when they adopted a new pantheon of dieties (the way that “Saturnalia” was adopted by the Christian faith as “the twelve days of Christmas.”)?
Lastly, what did the ancient greeks feel about their religion being “romanized” ? Was there any resistence to a conquering nation taking over their religion? Did the ancient greeks continue referring to their gods by their original names, or did they begin using the roman names as well?
What people often miss is that Greek and Roman religion were syncretistic, equating existing deities known to group X with those worshipped by group Y. The sorts of summaries of the two pantheons in Edith Hamilton or the World Book do not explore this intricate web of deities-equated-to-other-deities. But consider: Aphrodite/Venus is usually conceived of as goddess of love. But some Greek cities worshipped her as Aphrodite Urania, Queen of Heaven – definitely not something that matches the rather wanton lady of the typical short summary. Demeter/Ceres, goddess of agriculture, is a rather prim individual in those sources – but inspired orgiastic worship in Asia Minor. Diana the virgin huntress was also the Great Mother of the Gods in Ephesus – “Great is Diana of the Ephesians” from the book of Acts in the Bible does not reference the figure we know from the typical myths. Eros/Cupid, the minor figure who acts as Venus’s messenger in the “Bowlderized” myths, was in some traditions god of homosexual love, and in one account the creator god, supreme over all the rest.
Amon of the Egyptians was equated to Zeus, most of the Celtic gods of the Gauls were wedged into niches as “the Celtic Mars, the Celtic Hercules,” and so on. There is even, IIRC, a reference to the Germanic Loki as equivalent to Prometheus in one account, though this may be the speculation of the modern writer on myth and not the ancient author he was analyzing – it’s been a long time since I read that.