Roman religion was a set of things you did rather than a set of things you thought, and almost everything strange about the empire's treatment of Christians follows from that one fact.
The previous lessons have described a state that governed through cities and asked very little of its subjects. Religion is where it asked something, and the request was small: take part. This lesson works out what taking part meant, why the request was so easy for almost everyone to meet, and why the group that could not meet it ended up producing the only universal order the empire ever issued to its inhabitants before the edict of 212.
What the sacrifice was for
The Latin for the relationship is pax deorum, the peace of the gods, and it was understood as a bargain of maintenance rather than devotion. The community performed the rites correctly, at the right times, with the right words and the right animals, and the gods in return did not send plague, defeat, flood or famine. If the rites were done wrongly they were done again from the beginning, sometimes several times, because the fault lay in the performance.
Two consequences follow. The first is that there was no creed, no requirement of belief, and no religious authority to define one. Priesthoods at Rome were offices held by magistrates and senators, not a separate class, and the emperor from 12 BC held the chief of them. A Roman could think what he liked about the gods, and educated Romans wrote sceptical books about them while holding priesthoods, without any sense of contradiction.
The second is that the system was infinitely expandable. A new god was not a rival claim but an addition, and the empire absorbed Isis, Mithras, Cybele, Jupiter Dolichenus and dozens of local deities without difficulty. Where the state did intervene, as against the rites of Bacchus in 186 BC or against magicians and astrologers repeatedly, the worry was never doctrinal. It was the same worry the previous lessons found about fire brigades: organised bodies of people meeting privately.
The emperor among the gods
Into this framework the imperial cult fitted with almost no friction. In the Greek east, where honours to rulers were an old habit, cities built temples to Rome and Augustus within his lifetime and competed for the right. At Rome the etiquette was stricter: a living emperor received no cult, but a dead one could be voted divus by the Senate, and Augustus, Claudius, Vespasian and Titus were. Vespasian is said to have remarked on his deathbed that he thought he was becoming a god, which is a joke that only works if everyone understood the procedure and nobody quite believed the claim.
What mattered practically was not theology but the oath and the gesture. Swearing by the emperor's genius, burning incense before his image, and pouring a libation were the ordinary acts of a loyal subject, performed at the opening of a court, at a public dinner, on an accession. They were closer to a national anthem than to a communion, and refusing them looked like what refusing an anthem looks like.
The exemption that had a price
One group had a standing exception. Jews did not sacrifice to Roman gods, and Rome accepted this on the grounds of ancestral custom, which was a category Romans respected. Instead the Temple in Jerusalem offered sacrifices on behalf of the emperor, which satisfied the requirement of participation without breaching Jewish law, and Jewish communities across the empire were excused the imperial cult, allowed to send the Temple tax, and exempted from military service.
The revolt of 66 to 73 ended that accommodation without ending the exemption. After the Temple was destroyed in 70, Vespasian kept the tax and redirected it: every Jew in the empire, now including women, children and the elderly, paid two denarii a year to the treasury of Jupiter Capitolinus. A tax formerly paid to one's own god was now paid to the god of the people who had destroyed his house. Domitian enforced it aggressively, and Nerva made a point of stopping the abuses, striking coins announcing that malicious accusation under the Jewish tax had been abolished, which is a rare case of an emperor advertising the correction of his predecessor on the coinage.
The arrangement is worth holding onto because it defines the shape of the problem. Rome could tolerate a group that would not sacrifice, provided the group was an ancient nation with its own customs, was identifiable, paid something, and did not recruit.
Why Christians did not fit
Christians failed all four conditions. They were not an ancient nation, and in Roman eyes a novel practice had no claim on respect at all. They were not identifiable, since they came from every people and could not be told apart until they were asked. They refused sacrifice on principle rather than by ancestral custom. And they recruited, across households and classes, which meant the refusal spread.
That combination produced a genuinely novel category, and the state took decades to work out what to charge them with. Tacitus records the first attempt: after the fire of 64, Nero fixed the blame on a group popularly detested, whose founder Christus had been executed under Tiberius by the procurator Pontius Pilatus, and had them killed in ways Tacitus thought excessive enough to produce sympathy. He says they were convicted of hatred of the human race, which is a charge about attitude rather than about any act.
Example. Around AD 112, Pliny writes to Trajan from Bithynia asking how to try Christians, and describes what he has been doing. He asks the accused three times whether they are Christians, warning them of the penalty, and executes those who persist. Those who deny it he tests by requiring them to invoke the gods, offer wine and incense to the emperor's image, and curse Christ. Read the procedure. What is the crime?
The procedure answers the question, and the answer is that the crime is being a Christian. Pliny investigated what Christians actually did and found nothing criminal in it: they met before dawn, sang a hymn to Christ as to a god, bound themselves by oath not to steal, rob, commit adultery or break faith, and met again to eat ordinary food. He tortured two slave women who held office among them and found, in his words, nothing but a debased and extravagant superstition. Having established that the group commits no offences, he goes on executing its members.
That is only coherent if the offence is the refusal itself, and the test he applies makes it explicit, because it tests behaviour rather than belief: sacrifice, and you are released whatever you privately think. The state is not asking for faith and does not care about it. It is asking for a public act of participation and treating persistent refusal as contumacy, which a Roman court could punish almost by definition. Notice how sincerely puzzled Pliny is throughout. He is a competent administrator who has run into a category his law has no name for, and he is asking his emperor for one.
Now you. Trajan replies that Christians must not be sought out, that anonymous accusations have no place and are unworthy of the age, but that anyone properly accused and convicted must be punished unless he sacrifices. Is that tolerance?
Answer
It is a policy of not looking, which is different, and its effects were both real and precarious. Real, because if the state does not investigate and will not accept anonymous denunciations, then in practice being a Christian is safe unless a neighbour is willing to accuse you publicly and face the consequences of failing. That is why there was no sustained persecution for a century and a half, and why the martyr accounts we have are local episodes rather than campaigns.
Precarious, because the underlying rule is untouched: convicted, you die. The safety depends on the goodwill of neighbours, and goodwill fails exactly when a city is frightened. Plague, earthquake, famine or defeat were read as the gods withdrawing their favour, and a group that refused the sacrifices was the obvious explanation to hand. Tertullian's complaint that any disaster brings the cry of Christians to the lion is a description of the mechanism, not just a grievance. A tolerance that consists of a rule not being enforced will be enforced precisely when tolerance is scarcest.
How many, and how fast
Nobody counted Christians, and the sources that do give numbers are apologists with an interest in exaggeration. What can be done is a growth model, and it is more informative than it sounds.
Example. Suppose there were about a thousand Christians in the empire around AD 40, and suppose the movement grew at 40 per cent a decade, which is roughly the sustained rate observed in modern new religious movements. Where does that get you?
Forty per cent a decade doubles the number every 2.06 decades, so about every twenty-one years. Starting from a thousand in AD 40 gives around 7,500 by AD 100, 40,000 by 150, 218,000 by 200, 1.2 million by 250, and 6.3 million by 300, which is about ten and a half per cent of sixty million people.
That last figure is close to what historians independently estimate for the eve of Constantine, and the whole point of the exercise is that nothing dramatic was required to reach it. No mass conversions, no miracles of scale, no imperial favour: a modest rate, compounded for two and a half centuries. It also explains why the state's attitude changed when it did. At one in five hundred, around AD 200, Christians are a curiosity; at one in ten, around 300, they are a constituency, and any emperor doing arithmetic can see which way the curve is going.
The model is an assumption dressed as a calculation, and its honest status is this: it does not show that Christianity grew at 40 per cent a decade. It shows that a rate low enough to be unremarkable is sufficient to explain the outcome, which removes the need for any special explanation and puts the burden on anyone who wants one.
Now you. Pliny tells Trajan that the temples in his province had been almost deserted, that the sacred rites are now being resumed, and that fodder for sacrificial victims has found buyers again. How much should that be allowed to prove?
Answer
Very little about numbers, and quite a lot about something else. Around 112 the growth model puts Christians at well under one per cent of the empire, and no plausible figure for Bithynia empties its temples. Two corrections are available and both are probably operating. Christians were unevenly distributed, concentrated in cities and in particular regions, and Bithynia and Pontus were among the earliest areas reached, so local density could be many times the imperial average. And Pliny is writing to his emperor about his own handling of a problem, in a letter whose closing paragraph reports that the situation is improving under his management. Deserted temples now filling again is exactly the sentence a governor writes.
The useful reading is not as a measurement but as a symptom. What Pliny noticed was a fall in the sale of sacrificial fodder, which is to say that the effect of the new religion first became visible to the Roman state as a commercial one. A movement that changed what people bought was legible to a governor long before anything doctrinal was. Keep that in mind for the fourth century, when the state's adoption of Christianity has to be paid for out of the same kind of ordinary economic fact.
Decius, and the first order to everyone
In 250 the emperor Decius issued an edict requiring the inhabitants of the empire to sacrifice to the gods, pour a libation, taste the offering, and obtain a certificate from a local commission recording that they had done so in its presence.
Around forty-five of those certificates survive on papyrus from Egypt, and they are startlingly bureaucratic. A woman gives her name, her father's name, her age and a distinguishing scar, states that she has always sacrificed to the gods and has now sacrificed and poured libations and tasted the offerings in the commissioners' presence, and asks them to certify below. Two commissioners sign. It is a form.
Example. The edict, as far as anyone can tell from its text and from the certificates, never mentions Christians. What was it for?
It was a universal act of supplication, ordered because the empire was in trouble. The 240s had brought defeat on the Danube, a newly aggressive Persia and the beginning of the run of short reigns the next lesson describes, and the Roman response to disaster was always the same: the peace of the gods has been broken, so restore it properly and comprehensively. Decius did on an imperial scale what a city did after a bad omen.
The consequence for Christians was severe and incidental. For the first time the state was not waiting for accusations but requiring an act from everybody and issuing paperwork, so refusal now had a name, an address and a missing document. The persecution that followed produced not only martyrs but a mass of Christians who sacrificed, or who bribed commissioners for certificates without sacrificing, and the church spent years arguing about whether they could be readmitted. That argument mattered more in the long run than the deaths, because settling it forced the church to develop procedures for authority and forgiveness it did not previously have.
Now you. Decius's edict was universal, and the edict of 212 that made everyone a citizen was universal. What does the pairing tell you about where the empire was heading?
Answer
That the state was learning to address its inhabitants directly, as a single body, rather than through the cities and communities that had always stood in between. The earlier lessons described an empire that governed by delegation and asked almost nothing of individuals: a citizen was a citizen through his town, a taxpayer paid through his council. Both these edicts skip that layer. Everybody is a citizen; everybody sacrifices; everybody gets a certificate with their name and their scar on it.
That is the direction of travel for the rest of this course. The third-century emergency and Diocletian's reconstruction produce a state that is far more present in ordinary life, taxes individuals in kind, registers them, ties them to occupations, and eventually cares what they believe. The empire of Pliny and Trajan asked for a gesture and looked away. The empire that emerges from the third century asks for a signature.
The pressure that produced Decius's edict is the subject of the next lesson. Between 235 and 284 the empire lost more emperors than it had had in the previous two centuries, lost one of them to capture by a Persian king, broke into three pieces, and destroyed its own silver coinage. That it survived at all is the surprising part.