On the surface, it’s easy to assume that there are only minor differences between the gods worshiped by the Greeks and those the Romans beatified. Twelve important gods and goddesses stood at the pinnacle of the Greeks' Mount Olympus. The Romans, too, centered their mythology around 12 very similar gods and goddesses, so many scholars have decided that, upon conquering Greece, the Romans adopted their mythology, renaming the central characters. There is quite a bit of truth in this, but there are also a few differences that run deeper than a simple name change in the relationship between Roman and Greek mythology.
The Greeks wove many a story around the adventures of Zeus, Apollo, Aphrodite, and Ares, among others, from love affairs with one another to love affairs with human beings that resulted in a race of heroes. Their mythological deities lived in a mysterious universe that seemed simultaneously of this world — though high on a mountain — and outside of it. Greek storytellers used the divine relationships to explain natural and historical events as well as for entertainment. The Greek gods and goddesses were, essentially, a Hellenistic soap opera in which each new chapter built upon the ones before it.
During the 300-year period of Roman domination, Roman and Greek mythology overlapped and merged. The Romans brought with them their own pantheon but were intrigued by Greece’s rich culture, complex society, and glorious art. Wherever a connection could be made between a Greek and Roman god or goddess, the Romans were eager to forge it. In its earliest incarnation, Roman mythology continued to allow the deities to live on Mount Olympus.
With time, differences between Roman and Greek mythology began to appear. This is evident in the differences between the roles played by the Greek Ares, God of War, and his Roman persona, Mars. Ares, the more ancient of the two, is vengeful, terrifying, violent, and physical. His furious nature is tempered by his sister, Athena, who brings strategy, logic, and leadership to the game of war.
To the Romans, Mars was a multitasking god who presided over battlefields as well as agricultural ones. As the god of fertility, part of this job was to spread seed, just as the Romans did as they expanded their empire to the corners of the known world. Mars subsumed the Greek Athena’s prowess in military strategy and used war less as an end in itself and more as a way to parlay peace. Other differences between Roman and Greek mythology had to do with both the subtler aspects of personality in the 12 essential gods and goddesses and in the generations of their legitimate and illegitimate offspring.