A Comm for Historymemes

Nah, not exactly. The Romans gave a decidedly "own" twist to their mythologies and religion. Many of their deities are parallels of the Greek ones, but, well, different. Mars, as a god of war, was decidedly less barbaric and more cunning than his Greek counterpart Ares. It also mattered what archetype they invoked; Mars Ultor was specifically "Mars the avenger", whom was invoked when on a campaign of revenge against for example the Parthians who had stolen several Eagle standards.

Others are uniquely Roman and don't even have a direct Greek counterpart. Janus, the two-faced god of doors and new beginnings, was such a god. He was supremely important in all Roman religious cults and was invoked first, even before Jupiter, since he was held to be the "door to all deities".

Roman and Greek religion are commonly confused, or else Roman religion accused of ‘stealing’ the gods wholesale from the Greeks. The truth is much more complex - while the Romans saw Greek gods, like any other nation’s gods, as their own gods under a different name (Mercury is Hermes, just like Mercury is Odin), and there was a great deal of cultural exchange between the Greeks and Romans, Roman religion was Italic in origin and had significant qualities that set it apart from the Greek worship of the gods.

There is only a little native Roman mythology about the gods, however - in very typical Roman fashion, it seems that that the gods existed and that it was important to keep contracts with the gods was enough for them - why bother with pretty little details with that practical concept settled? In that, the Romans took a great deal of Greek mythology about the great deeds and histories of the gods and accepted it without further questioning.