Writers in Ancient Greece, when traveling in or discussing other lands, had a habit of identifying the local gods with their own gods back home. For example, the Egyptian god Amon was deemed an interpretation of Zeus. This incorporation of other cultures and religions into your own is also known as Syncretism.
The Romans built on the Greek tradition, combining Etruscan Mythology and Greek Mythology into their own myths and religious beliefs. So now, Amon is Zeus, both of whom are Avatars of Jupiter. In some cases, these blendings were natural, and made perfect sense. In other cases, the Greek and Roman versions of a Mythological character didn't match up so well - moody Ares is a far less humane character than disciplined Mars, for example. The Romans didn't let this stop them.
The Romans didn't stop at Greece, either, they took the concept much further. When they arrived in what is now Germany, they interpreted Thor to be Heracles. Upon reaching what is now the British Isles, they reported back that the Celts worshiped Mercury, though the local name was Lugh. They did similar things where ever they went, and the Romans went all over the place. It all gets pretty messy.
It goes both ways. The Germanic peoples also adopted aspects of the Roman gods into their own beliefs. This muddies up the situation even more, as Jupiter is linked to Thor, who is also connected to Heracles. In a round-about way, this almost makes Heracles into Jupiter, after the fact.
Here's a list of Mythological Characters, including their names under various systems. As illustrated above, some of these connections make a lot more sense than others.
- Interpretatio Cthulhiana - an attempt to identify the entities of the Cthulhu Mythos with entities from traditional mythologies
Game and Story Use
- Perhaps the gods are some sort of precursor race, and only a handful exist. They infiltrate numerous cultures over the ages, manifesting and influencing. This Interpretatio Graeca stuff isn't just nonsense, it's the truth.
- These correspondences, renaming, and "lumping together" of the gods might be a source of great annoyance to the gods. Especially if they are Mythagos and find their existence mutated by belief. Quit thinking that about me - it's your fault if I become what you imagine!
- On the other hand, if the Gods Need Prayer Badly, they won't mind mooching in on the territory of another god. Heck, it might be something they command the priests to do. Share and share alike, that's how Jupiter rolls.
- A game set in Greece, Rome, or Germany can take all kinds of cues and inspiration from a wide body of myth, blending them together into a divine smoothie.
- Many "deities" of the Cthulhu Mythos are treated similarly. Who knows what kind of entity is really lurking behind an apparently benign mask?