The primary religion of ancient Rome was initially polytheistic, centered around the worship of various gods and goddesses like Jupiter, Juno, and Mars. The Romans practiced a form of religion that incorporated rituals and sacrifices to appease these deities, which was deeply integrated into public and political life. Over time, especially after the reign of Emperor Constantine in the 4th century AD, Christianity began to rise in prominence, eventually becoming the official religion of the Roman Empire by the end of the century, profoundly influencing Western civilization.