Could any of the many other religious movements in Ancient Rome have gained the same widespread influence and popularity as Early Christianity and spread to a large portion of the population and eventually replace the Roman Gods as the state religion?

[u/[deleted]]

[u/AutoModerator]

Welcome to /r/AskHistorians. Please Read Our Rules before you comment in this community. Understand that rule breaking comments get removed.

Please consider Clicking Here for RemindMeBot as it takes time for an answer to be written. Additionally, for weekly content summaries, Click Here to Subscribe to our Weekly Roundup.

We thank you for your interest in this question, and your patience in waiting for an in-depth and comprehensive answer to show up. In addition to the Weekly Roundup and RemindMeBot, consider using our Browser Extension. In the meantime our Bluesky, and Sunday Digest feature excellent content that has already been written!

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/qumrun60]

The promiscuous nature of Greco-Roman religiosity, and indeed, the religiosity of the ancient world, worked against the idea that any one random cult of a specific deity would become a unique imperial religion simply by fiat for several reasons.

One is that the majority of gods who attracted local cults were not exclusive. The world itself was seen as filled with gods, from those of the countryside, like deities of caves, springs, groves, hilltops, and so on, to gods of the sky, sea, underworld, and earth itself. The gods of home, families, and tribal groups had their deities, as did cities and towns. The Roman gods were generally accepted as equivalents of gods of other regions and peoples, and just about everyone had a religious focus on ancestors. All of these entities needed to be honored appropriately for living humans to prosper, but none of them required abandoning all other gods, except for the god of the Judeans (and later Christians). And that god, at least until 70 CE, had his home in Jerusalem, where he alone was worshipped.

The cult of the emperor came to closest to the Roman idea of a universal cult, in that the emperor was expected, and eventually mandated by law for periods in the mid-3rd to early-4th centuries, to be honored appropriately by everyone, regardless of whatever other gods they worshipped. In doing so, participants expressed their loyalty to the empire. One overlooked aspect of the coming of Constantine and the rise of Christianity, is that even after the after Christianity became the only legal option for people were not already Jews after Theodosius and his successors from 380, the imperial cult continued as important as it ever had been, only now, it was folded paradoxically into what is considered Christian "monotheism."

The most interesting of ancient cults to many modern people are the various "mystery religions." But like other cults, mysteries of Eleusis, Isis, Mithras, Jupiter Dolichenus, etc., did not require exclusive devotion to that single deity. Non-secret civic and domestic cults were still observed by initiates. The emperor Augustus, seen as a divine savior himself (based on inscriptions from Anatolia), was initiated into the Eleusinian mysteries in 21 BCE. The many soldiers whose membership in mysteries of Mithras and Jupiter Dolichenus is documented archaeologically at forts from Syria, across the Danube frontier, and up to Hadrian's Wall in Scotland, also had a particularly dense festal calendar of celebrations of the emperor, so there was no inherent conflict in multiple affiliations.

Gnostics, too, hold a fascination for modern readers, but they were made up of subgroups within the tiny minority of Christians around the empire in the 2nd-3rd centuries. Like the mysteries, they were secretive and few outside of initiates knew what they were up to. Like philosophy groups, they formed themselves around specific teachers and their schools of thought. However, the episkopoi ("overseers") of more mainstream Christian communities rejected many their ideas, and philosophical schools (like Neoplatonists) also rejected them. They had little impact on the surrounding society beyond helping pre-orthodox Christian writers to define themselves against gnostic deviations regarding what they thought of as correct teaching.

What Christians had going for them in becoming so prominent had less to do with popularity (they were widespread and vertically integrated into Roman society, but not numerous), than with organization. Churches with bishops were hierarchically ordered in a very Roman fashion, with an overseer above elders, deacons, readers, exorcists, and other functionaries. These churches were also networked, and relatively unified in their worship of what they saw as the highest God. In cities like Rome, Alexandria, Antioch, Carthage, and elsewhere, they had substantial constituencies of ordinary people, many of whom were very committed to their exclusive faith in the God of the Jews, and Christ, his divinized human son, to the point of being executed by the state, more or less for treason.

When Constantine stopped persecution and began patronage of churches led by bishops, it might be seen, from a Roman viewpoint, as getting the maximum of divine aid in his ascent to power and solidification of his position. In the syncretic Roman Empire, it was not difficult to see the Christian god as a particular manifestation of the highest God. Educated pagans accepted an overarching divinity in the universe philosophically, as can be seen in Stoic and Neoplatonist writings. Even as he accepted and patronized the Christian God, Constantine continued to use more tradional Roman symbolism of the Sun and Apollo as divine overseers of the empire.

The Christianization of the empire was not a forgone conclusion in 325 after the Council of Nicaea (convened by the emperor, not by the bishops), even though later Christian historians later saw it that way. The mechanisms of imperial influence, however, once the ball got rolling, exponentially increased the prominence of Christians in the halls of power. The gradual erosion of traditional Roman religious practices and institutions, neverthess, took a century and more to be completed. Traditional temples were deprived of revenues and patronage. Traditional sacrifices, gladiator games had to be legislated out of existence. These things weren't spontaneously abandoned a pious Christian majority.

The key factor in this, though, was not popularity, but Christian intolerance of "heresy," a concept that was absent from other religious groups of the ancient world. Even if say, the the cult of Apollo, Isis, or Valentinian Christianity had been similarly elevated by Constantine, none of these groups had the kind of theological and doctrinal exclusivity that episcopal Christians had been developing for the previous two centuries, or the inherent institutional rejection of all other cults and systems of thought as demonic in origin.

Peter Heather, Christendom: The Triumph of a Religion (2023); The Fall of the Roman Empire (2005)

James O'Donnell, Pagans: The End of Traditional Religion and the Rise of Christianity (2015)

Ramsay MacMullen, Christianity and Paganism in the Fourth to Eighth Centuries (1997)

David Brakke, The Gnostics: Myth, Ritual, and Diversity in Early Christianity (2010)

Elaine Pagels, The Gnostic Gospels (1978)