Robin Lane Fox's 1986 book Pagans and Christians is subtitled (pedantically) "Religion and the Religious Life from the Second to the Fourth Century A.D., When the Gods of Olympus Lost Their Dominion and Christianity, with the Conversion of Constantine, Triumphed in the Mediterranean." (At least, that's what's on the cover of my edition; apparently later editions condense the subtitle substantially.) That's not a bad summary of the material covered, but a rotten summary of the premise, which goes something like this. Between around 1979 and 1985, there came to be published an awful lot of scholarly compendia of really good primary source archaeological material from the 2nd through the 4th centuries, especially from Egypt and Asia Minor. Lane Fox's idea was to try to use that material to see what the physical evidence, and what the contemporary non-Christian written evidence (especially unofficial stuff like letters and wills), had to say about the rate of spread of Christianity over the first 250 or so years after Jesus' death, and see if that archaeological record could be squared with the version of church history that the church itself compiled, and that it teaches to this day in seminaries. That same church history gives a very important narrative explanation of not just how fast Christianity spread, but how and why Christianity spread. Lane Fox set out to see if their explanations of why and how could also be squared with the archaeological record.
Conclusion? No. Not even close. Church history is largely a pack of heavily biased lies. Now, honestly, how surprising is that, anyway? Victors write the histories, and during the Dark Ages it pretty much was the Christians who wrote the history of the Roman Empire. It's entirely unsurprising that they remember themselves as the good guys, the non-Christians and various Christian heretics as bad guys, themselves to have been continuously and bitterly hunted down for persecution and slaughter by the bad guys, and their ultimate success to have been both inevitable because of their innate goodness and yet somehow evidence of God's miraculous power at the same time. I'm not saying that a history that says that has to, by definition, be false, but let's face it -- it's what they'd say, and even believe after a generation or two, whether it was true or not, now, isn't it? What Lane Fox gets credit for, among professional historians, is for realizing that late 20th century scientific techniques of history and archaeology provide ways of treating church history as a testable hypothesis: if history had happened the way that the church fathers said it did, then when historians looked in certain places they would have to find certain kinds of evidence. If no such evidence is found, then the hypothesis founders.
But here comes the first thing that makes the book a slog to get through: Lane Fox knew that in no small part he was writing for a very hostile audience. The particular historical specialty that he was writing about is one that's heavily dominated by theologians, for whom the historical record left by the church fathers was established history, long settled and long-ago proven. Knowing this, when he sets out his experimental proofs and then when he lays out the archaeological and epigraphical and historical evidence, his text can most charitably described as excruciatingly methodical. A less charitable way to put it would be to call it plodding. I found it terribly hard to read more than a half dozen or ten pages in a sitting if for no other reason than I kept wanting to yell at him through the page, "okay, get on with it already!" And in particular, the thing that I wanted him to get on with was to answer the question, "okay, if it didn't happen in the way that the church fathers said and for the reasons they said, how and why did it happen?" If, has he demonstrates, Roman government was no more corrupt or disrespected than it had been any time in the previous four or five centuries, if upper class financial and sexual corruption were no more awful nor any more complained about than any time in the previous four or five centuries, if the impact of the philosophers and other atheists over pagan religious sentiments can be shown to have been negligible at the time that Christianity experienced its greatest growth, if the supposed inevitable drift towards mysticism and monotheism can be demonstrated to have been non-existent, if pagan oracles and the public celebrations ordained by them were experiencing their greatest popularity and growth at exactly the same time that Christianity was growing, and if failures of Christianity can be shown to have been blamed by the public for just as many or more natural and economic disasters as the supposed failures of the pagan gods (all of which points Lane Fox demonstrates and weary but irrefutable length), then, well, what did happen?
And that leads to the second thing that made the book a bit of a slog to get through. As he was making these arguments, I kept looking at the structure of his arguments, and the conclusions to the sections and chapters, for clues foreshadowing the ultimate explanation that I assumed he must have been leading towards. And I kept scratching my head and concluding that maybe I was missing the point. No, I wasn't. He doesn't really have an explanation, or at least he didn't in 1986 when he finished the book. That was a heck of a shame, when I realized it, because one of the things I was hoping to get out of this book was an answer to the question, why did it work when Emperor Constantine ordered his subjects to change religion if it didn't work when Emperor Julian gave the same order going back the other way? I finished the book somewhat disappointed ... but only somewhat disappointed. Lane Fox is much more confident of his refutation of the arguments in church history than he is in his own hypotheses, but scattered throughout the books are hints towards some alternate hypotheses.
One trend that Lane Fox shows clearly that Christianity benefited from was a weird Roman fad of the late 1st and early 2nd century, but not the one you're thinking of (mystery religions, I'm assuming). See, the Zealot Rebellion, Israel's attempted secession from the Roman Empire, struck at the Roman Empire's self image the way 9/11 struck at America's. And then as now, it created a fad among public intellectuals and shallow poseurs, people like myself now, to want to understand the enemy, to want to understand what drove this weird alien culture to such desperate acts of suicidal terrorism. The net effect on the Roman Empire was a brief fad for "Chaldeanism," driven by educated Romans' and Greeks' being impressed by one particular claim that the Jews made, namely that their religious and spiritual traditions were continuous and at least 2500 years old at the time, that they went all the way back to primitive Babylonia without any changes in between. Poppycock, of course, albeit poppycock that's still taught in some churches and synagogues today. But in a culture that revered ancient tradition but that had no meaningful history that went back more than 800 or 1000 years, a claim to a 2500 year history was inherently impressive. Except, of course, that because of the rebellion Jews themselves were seen as recalcitrant, stubborn, crude, murderous savages -- spiritual and educated, but savage nonetheless. In its early years, Christian preachers cheerfully traded on the curiosity and spiritual appetites of people who were all too eager to learn the secrets of ancient Chaldean religion so long as they didn't have to learn it from those icky Jews. But, Lane Fox shows, that didn't get them much farther than Asia Minor and a few scattered wealthy households in the western empire, in maybe a half dozen or dozen cities.
In his nicest piece of historical detective work, Lane Fox shows how the next phase of Christian expansion was, well, something of a sleazy scam, and that it was public outrage over the perceived sleaziness of that scam that sparked off periodic bouts of brief localized persecution. See, he shows that it happened like this: an early theological understanding of the doctrines of Christ and of Paul was that baptism washes away all sins that you've committed up to the point of your baptism ... but that those are the last sins you can ever have forgiven, after that you better watch yourself. In those first couple of centuries, this lead to a kind of spiritual athleticism, as Christians openly competed over who could be the least tempted by sin, with the highest prizes going towards people who swore off sex. This cult of virginity didn't require that you had never had sex, only that you never had sex ever again after you were baptized. But a century or so in, Christian bishops in Egypt and Asia Minor stumbled upon an interesting quirk in Roman inheritance law. It wasn't uncommon of Roman men, worried about the mothers of their heirs possibly dying in childbirth, to insist on marrying very young women. But this meant that any woman who did survive the birth of the requisite number of heirs and spares was almost certainly going to outlive her husband. Who inherits his wealth? The compromise that Roman law worked out was that in a narrow legal sense, she did. The catch was that the law gave her almost no legal way to spend any of it, with the intention of thereby forcing her to remarry, and thereby pass that wealth on to a new husband who would take it over and control it. What the bishops discovered after the first time or two that they converted wealthy widows was that the cult of secondary virginity left them unable to remarry. Not marrying left them in ownership of substantial wealth. And the bishops figured out ways for those widows to legally transfer their late husbands' wealth, in steady dribs and drabs, to the local Christian poor -- and, of course, to the local Christian bishop. Any substantial sums of money that she gifted to these "temples" that existed only in the widows' own back rooms was in theory being spent by the bishop, but the bishop knew which side his bread was buttered on; she controlled his budget, including his salary.
Lane Fox shows that as this idea spread, it had three consistent results. One, an awful lot of rich women saw this as a great way to gain economic independence in a male-dominated world, and eagerly converted to Christianity, sometimes not even waiting until their husbands died. Secondly, crowds of wealthy and politically powerful regional officials saw these filthy hippy homeless guys moving into these rich widows' houses, presumably seducing them without marrying them, and tricking these women into liquidating great estates and powerful investment businesses that the local economy depended on to hand out to that worthless perverted hippy "bishop's" equally filthy and sick and dirt-poor moocher friends; unsurprisingly, they often got permission from Rome to crack down on this and chase them out of town. But thirdly, since when push came to shove what the bishops were doing was legal and since so few actual sexual scandals were ever proven, it did establish a Christian reputation for being a counter to some of the more obscene accumulations of wealth in the late Roman empire, it gave Christians the budget to begin to compete at least halfway successfully with the Pagan temples in public generosity and public charity.
But even then, Lane Fox shows beyond all shadow of a doubt, before Constantine's conversion the total Christian population of the empire probably didn't amount to more than a couple of percent. That brings him up to Constantine himself. Lane Fox sees Constantine as a scheming small-time politician, stinging over his relatively modest family background and perceived snubs, who through sheer ambition clawed his way up into one of the seats on the Tetrarchy, the four-way division of imperial authority that was what passed for a system of checks and balances in the wake of the last round of Roman constitutional reforms. It wasn't enough for him. He used what authority he had to raise an army that he believed was big enough to (deeply illegally) crush and subjugate the other 3 Tetrarchs, to make him the absolute unitary monarch of Rome. The catch was that no Roman army would march into battle without "favorable omens," that is to say, without at least one priest of at least one religion who was willing to sign off and say that in his opinion, this battle was okay with at least one of the gods. And since what Constantine was trying to get religious permission to do was to stage a military coup d'etat that would destroy the balance between the four branches of government, to his consternation Constantine found out that not one single pagan priest anywhere he could find could be bribed enough to bless his attack on the other three tetrarchs. Lane Fox's interpretation of the conversion of Constantine, "in hoc signe vinces," is that Constantine finally did find one religious official who would sign off on his war: a Christian bishop. That bishop was taking, if I may call it that, one hell of a gamble, blessing an aggressive civil war. But the gamble paid off: Constantine won.
And what Lane Fox shows is that the effect on Constantine himself was probably unpredictable, even by that bishop. Constantine's ego was so immense that he spent the rest of his life citing it as proof that the Christian god was the only real god that only the Christian god has been smart enough to recognize that Constantine should be the unchallenged emperor of the whole world. Since none of the other gods had been willing to sign off on Constantine's dictatorial reign, they were obviously false gods. So, okay, you can see the Roman people rolling their eyes over this ... privately. Lane Fox shows that (unsurprisingly) the various government officials in Constantine's government couldn't tell, themselves, how seriously Constantine actually meant this, or what that meant that they were supposed to do. But eventually they figured it out because Constantine's actions made it clear for them. No Roman citizen would have been scandalized by his first step; Constantine diverted a good chunk of his own wealth, and his modest personal slice of the Roman government budget, to subsidizing the temples of his own favorite god. This was a long-standing perq of Roman government, one that the tetrarchs had enjoyed themselves. Nobody thought it terribly scandalous because taste in gods changed with every change at the top of the government, eventually everybody got their turn, and it's not like these were the only public contributions going to temples. On the contrary, in the early chapters Lane Fox showed that what drove the successes of the pagan temples and oracles in the 2nd and 3rd centuries was a Roman formalization of an earlier custom: certain powerful Imperial and regional political offices were only offered to people with a reputation for having demonstrated their "civic mindedness" by having donated large sums of money to at least one temple. Which temple? Didn't matter, as long as it was local. But then Constantine dropped his real bombshells: he declared a specific tax exemption only on inheritances that were donated to Christian churches, and he showed a marked preference for Christian officials for the really important public government offices. It didn't take very many years of that, and unfortunately Constantine had enough years, for the wealthy people who'd always funded paganism for centuries before that to get into the habit of equally competitively funding Christianity, and Christianity only. Pan didn't die of shame, he didn't die because of Christ's sacrifice, he didn't die of rising public apathy. He was starved to death.
As you can tell from this summary, I'm very glad I read this book, because I got a lot to think about out of it. But I'll tell you what, though: it's not enough to want to know what's in this book, you've got to be really highly motivated if you're going to finish it. So if you're really highly motivated, I recommend this book. Otherwise, you can probably stand to skip it.