Roman religion in the middle and late republic, a period stretching from the beginning of the Punic Wars in the early third century to the death of Julius Caesar and the ascension of the first emperor Augustus in the late first century bce, concerned itself with the city of Rome. This statement may seem to be a truism, but it actually expresses the two fundamental features of Roman religion: that the Roman religious system concerned itself primarily with the health of the Roman community, and that it was a religion of place. The primary purpose of the public religious system was to protect and enhance the community of the Romans; the modern notion of a separation of church and state would have been unthinkable to the Romans. The welfare of the city and its inhabitants was ensured by a series of rituals by which the Romans attempted to secure the goodwill of the gods, and the primary role of the religious authorities in Rome was to ensure that these rituals were performed in the proper way, at their proper time, and in their proper place. The second point follows from the first: Roman rituals were performed in specific places around the city of Rome in order to protect the city. Some of these places had been considered sacred from time immemorial, while others had gained their status over the years, but each location had its specific ritual that needed to be performed on that spot, and at a specified time of the year. Religion permeated almost every element of both space and time for the inhabitants of Rome, leading the Romans to believe themselves the most religious of all people and to ascribe their military success to their superior cultivation of the gods (Cic. Har. resp. 19).
To ensure the favor of the gods, the Romans relied on the correct performance of ritual (orthopraxis). Questions of belief or morality were not central to the religious system, though this statement should not be misinterpreted as meaning that the Romans did not believe in their gods or that they did not concern themselves with morality. The Romans did have a well-developed sense of what constituted appropriate behavior, but they did not believe that moral standards emanated from divine pronouncements; for reasons we shall explore below, divine revelation in the form of specific commands played a very limited role in Roman religion. In regard to belief, such questions are exceedingly difficult to answer at all times, even more so for an ancient society that has left us limited records. The evidence available from Rome dates mostly from the middle of the first century bce, which makes it virtually impossible to know what Romans of an earlier period may have believed. This evidence suggests that late republican Rome may have been largely similar to modern societies; some members of the community, such as Cicero, can be found expressing some skepticism, but there is no reason to think that the overall level of belief was any greater or lesser than today. Romans performed religious actions on a regular basis in different contexts - in public as citizens, in their houses as members of their family, and perhaps on their own - but for the Romans these formed a continuum of religious activity. While the following remarks concentrate on the public religious system, that focus is not intended to privilege that sphere as more important, but acknowledges it as the most visible manifestation of religion in Rome, in terms of both the surviving evidence and its impact on the city as a whole.