The Roman gods were adapted from the Greek gods and most of them renamed. Their personalities were seen as more rigid, disciplined, and war-like.
Some gods were unique to the Roman pantheon, like Pompona. Some were basically identical to the Greek, like Nemesis. And among the central pantheon, which was considered the most important god changed.
While Jupiter (Greek Zeus) was still in charge, the Romans due to their military culture took as patron Mars Ultor (Greek Ares), god of war. He was not seen as particularly powerful in the Greek pantheon, as the Greeks as a culture were more focused on the arts and philosophy. The Greeks had as patron Athena (Roman Minerva), goddess of strategy, wisdom, and the arts- she was greatly weakened in the Roman pantheon. The Romans, when they conquered the Greeks, took the statue of Athena from the Parthenon to symbolize their defeat.
The religion of the Romans was greatly influenced by the Etruscans, a people generally thought to have come from Asia Minor. The practice of divination definitely links the religion of the Etruscans to that of the Babylonians. For example, the models of clay livers used for divination found in Mesopotamia resemble the bronze model of a liver found at Piacenza in the region of Emilia-Romagna, Italy. So, when the Romans adopted the Etruscan deities they were, in effect, receiving a Babylonian heritage. (See ASTROLOGERS.) The Roman triad of Jupiter (the supreme god, a god of the sky and light), Juno (the consort of Jupiter regarded as presiding over matters of particular concern to women), and Minerva (a goddess presiding over all handicrafts) corresponds to the Etruscan Tinia, Uni, and Menrva.