Rome's most unusual institution was not its army or its law but its willingness to turn conquered people into Romans, and no other ancient state did it on anything like the same scale.
The previous lesson ended with local notables paying for the privilege of governing their own towns on Rome's behalf. This lesson asks what they were buying. The short answer is membership, in a status that could be inherited, earned, bought or given, and that spread until it covered everyone. Along the way the ruling class of the empire stopped being Italian, and the emperors themselves stopped being Italian, without anybody deciding that this should happen.
What the status actually did
Roman citizenship was a bundle of legal capacities rather than a nationality. A citizen could contract a marriage recognised in Roman law, so his children inherited from him under that law; he could own property in the Roman form, make a valid will, and sue in a Roman court. He was exempt from the poll tax that provincials paid. He could not lawfully be flogged or tortured by a magistrate without trial, and he had the right of appeal, which by the imperial period meant appeal to the emperor.
Those protections were real and they were also patchy. Governors flogged citizens when it suited them and were occasionally prosecuted for it, and the status did more for a rich citizen than a poor one, because enforcing it required somebody to complain and be listened to. But the exemptions had cash value and the legal capacities had commercial value, and the poll tax exemption alone was worth having in a province like Egypt.
The one thing citizenship did not do is what a modern reader expects: it carried no vote worth using. The assemblies at Rome had stopped legislating under Tiberius, and a citizen in Gaul was never going to travel to Rome anyway. It was a legal status and a claim on protection, not a share of political power. That is precisely why it could be given away so widely.
Counting the Romans
Augustus recorded three censuses in the Res Gestae: 4,063,000 citizens in 28 BC, 4,233,000 in 8 BC and 4,937,000 in AD 14. Tacitus gives a further figure from Claudius's census of AD 47: 5,984,072. Four numbers across seventy-five years, from two independent sources, and they let you watch the status spread.
Example. Between AD 14 and AD 47, the citizen body grows from 4,937,000 to 5,984,072. Can natural increase account for that?
The rise is 1,047,072, or 21.2 per cent in thirty-three years, which is an annual growth rate of 0.58 per cent. That is far above what a pre-industrial population sustains. Ancient populations grew, when they grew at all, at something nearer 0.1 per cent a year, and at that rate the citizen body of AD 14 reaches only about 5,103,000 by AD 47. So roughly 880,000 citizens have to come from somewhere other than births.
The sources are known and they add up. Every slave formally freed by a Roman owner became a citizen, which is a Roman peculiarity and a large flow in a society with millions of slaves. Every auxiliary discharged after twenty-five years became one, and at around 5,000 discharges a year over thirty-three years, counting the children included in the earlier grants, that alone is several hundred thousand. Add grants to individuals, to whole towns, and to the magistrates of Latin communities year by year. The honest qualification is that we do not know for certain what the census counted, whether adult males alone or men, women and children, and the answer changes the absolute size of the citizen body by a factor of three. It does not change the growth rate, because the same basis was presumably used each time, and the growth rate is what the argument rests on.
Now you. The last well-attested Republican census, in 70 or 69 BC, returned 910,000. Augustus returns 4,063,000 in 28 BC. What happened, and what should make you cautious?
Answer
The obvious cause is real: the Social War of 91 to 88 BC ended with citizenship extended to the whole of Italy south of the Po, which is the story the earlier course on the Republic tells, and it should multiply the citizen body several times over. A ratio of about 4.5 is roughly the right order for adding all Italy to Rome and the Latins.
The caution is that the two numbers may not be counting the same thing. Historians have argued for over a century about whether Augustus's censuses counted adult men, as the Republican ones are usually thought to have done, or all citizens including women and children. Take the first view and the citizen population of Italy in AD 14 is enormous and Italy is very densely settled; take the second and it is modest. The choice affects almost every estimate of ancient Italian population that has ever been published, and there is no decisive evidence either way. This is worth sitting with, because it is the normal condition of the subject. A number can be securely transmitted, honestly reported and still not tell you what you want, because the definition behind it is lost.
The ways in
Birth to two citizen parents was the ordinary route. Beyond it, four doors stood open.
Manumission was the widest. A slave freed by proper procedure became a citizen, with some restrictions on himself and none on his children, so the descendants of slaves were full citizens within a generation. Military service was the second: the auxiliary diploma of the previous lesson, arriving five thousand times a year. The third was office. In a community holding Latin rights, the annual magistrates and often their whole families became citizens on leaving office, so an entire local elite converted itself over a couple of decades. Vespasian granted Latin rights to the whole of Spain in the early 70s, which put several hundred communities on that escalator at once.
The fourth door was the emperor's personal grant, and it could be bought.
Example. In the Acts of the Apostles the tribune commanding the garrison in Jerusalem is about to have Paul flogged, discovers he is a citizen, and says that he acquired the status himself for a large sum. Paul replies that he was born to it. Read the exchange as evidence.
It gives you three things at once. First, the protection was operative: the tribune stops the flogging immediately and is alarmed, which means the rule was known to bind even a soldier in a distant province. Second, the status was purchasable, presumably through officials at court who arranged grants for a fee, and the tribune's name in the text, Claudius Lysias, tells you which emperor's reign he bought it in, because a new citizen took the name of the man who made him one. Third, and most interesting, birth outranks purchase in the exchange. Paul's reply is a small piece of social one-upmanship, and it only works if everyone present understands that a bought citizenship is second best. That is the ordinary fate of any status that can be acquired: it keeps its legal content and loses its social edge, and the edge is what people are actually competing for.
Now you. New citizens took the family name of the emperor or patron who enfranchised them. What does that convention allow a historian to do?
Answer
Date and trace enfranchisement across the whole empire, from names alone. A man called Tiberius Claudius Something in Asia Minor descends from someone made a citizen under Claudius or Nero; a Marcus Ulpius from a grant by Trajan; a Titus Flavius from the Flavians, and in Spain that usually means the Latin grant of the 70s. Since inscriptions and papyri survive in tens of thousands, this turns a naming habit into a distribution map of who was enfranchised, where and when, entirely independent of what any literary source says. It also gives the single best piece of evidence for the edict of 212, as the next section shows. The limit is that a name records only the grant, not the man's origin or language or how Roman he felt, and one of the persistent temptations of this subject is to read a Latin name as evidence of a Latin mind.
Claudius, the Senate, and two versions of one speech
In AD 48 the emperor Claudius proposed that leading men from Gallia Comata, the parts of Gaul conquered by Caesar less than a century earlier, should be eligible for the Senate. We have his speech twice: as Tacitus wrote it up in the Annals, and as it was actually delivered, because the Lyon assembly had it inscribed on bronze and a large part of the tablet survives.
Compare them and you get a rare controlled experiment in how ancient historians work. Tacitus gives a tight, well-organised argument: Rome has always taken in outsiders, from Sabine kings onwards; Sparta and Athens fell because they held their conquered at arm's length; what is now old was once new. It is lucid, forceful and about a third the length of the real thing.
The bronze shows Claudius wandering. He digresses into the ancestry of the Etruscan kings, interrupts himself to acknowledge that he is going too far back, worries about what people will say, and defends his own antiquarian learning. The argument Tacitus reports is genuinely in there, and so is a great deal that Tacitus cut.
Example. Tacitus did not invent the speech and did not reproduce it either. What is the right conclusion about his method, and how far can it be generalised?
That he worked from the substance and rewrote the form. The historical content, the precedents, the appeal to Rome's history of absorption, the answer to the objection that Italians should be enough, is all present in the original; what Tacitus supplied is compression and shape. So for this one speech we can say that he is reliable about what was argued and unreliable about how it sounded, which is roughly the standard an ancient reader expected, since a historian was supposed to give a speaker the words appropriate to the occasion.
The generalisation has to be careful, and in two directions. Favourably, Tacitus had access to the acta senatus and evidently used them, so his senatorial debates rest on record rather than imagination. Unfavourably, this is one speech, one that happens to have been inscribed because provincials were proud of it, and it is exactly the sort of case where a historian is likely to have been careful. It does not license trusting the speeches in Tacitus's account of Tiberius's court, where no record was public and the whole point of the scene is often what could not be said aloud. One verified instance raises the odds; it does not settle the class.
Now you. The Senate resisted. Within a century the resistance had become irrelevant. Why?
Answer
Because the recruitment was decided by the emperor, not the Senate, and it ran continuously. Senators were needed at a fairly steady rate, since senatorial families died out quickly, and the emperor filled the gaps from wherever he liked. Under Vespasian something like one senator in six was of provincial origin; by the middle of the second century provincials were a majority of those we can identify, first from Spain and Gaul and Africa, later from the Greek east. Trajan, made emperor in 98, came from a family long settled at Italica in Spain, and Septimius Severus in 193 was born at Lepcis Magna in Africa and reportedly kept the accent. No decision made this happen: it is the accumulated effect of a hundred and fifty years of individual promotions, each of them unremarkable. Institutions of this kind are usually transformed by rates rather than by resolutions, which is why the debate of 48 reads as important and the outcome had almost nothing to do with who won it.
The edict of 212
In 212 Caracalla granted Roman citizenship to all the free inhabitants of the empire. The text survives, badly damaged, on a papyrus from Egypt, in a Greek version whose opening gives a pious reason: the emperor wishes to bring all his people to the gods in thanksgiving for his own preservation. There is an exclusion clause naming the dediticii, a category we cannot securely identify, and it evidently mattered to very few.
Cassius Dio, writing a generation later and hostile, says the point was money: certain taxes, notably the five per cent on inheritances, fell on citizens only, and Caracalla had just doubled that tax to ten per cent. Universal citizenship makes a citizens-only tax into a universal one. The motive is plausible, the arithmetic works, and it is not the whole story, because the edict also removed the poll tax basis in some provinces and Dio wanted Caracalla to look grasping. The safest reading is that a fiscal motive and a religious one are not in competition: the grant was cheap to make, useful to the treasury, and it stated a fact that a century of drift had almost brought about anyway.
What is genuinely striking is how little seems to have changed. There was no celebration recorded, no crisis, and no rush of new privileges. The best evidence that anything happened at all is the naming habit: from 212 the papyri of Egypt fill with people called Aurelius, Caracalla's family name, appearing suddenly in front of names that had been Greek or Egyptian the year before. Whole villages of Aurelii, in documents about donkeys and rent.
What was left to be unequal about
The reason so little changed is that legal distinction did not disappear; it moved. Across the second century Roman law had been developing a division between honestiores, the respectable, meaning senators, equestrians, soldiers and town councillors, and humiliores, everyone else. The two were punished differently for the same offence: the honestior was fined, exiled or beheaded, the humilior was beaten, sent to the mines, thrown to the beasts or crucified. By the time everyone was a citizen, the protections citizenship had once carried against flogging and degrading execution belonged to rank instead.
That is the thing to carry forward. A society does not become equal by extending a status to everyone; it re-founds the inequality on a distinction the extension does not touch. The empire ended up with universal citizenship and a sharper legal hierarchy than it had begun with, and the second development is what shapes the late Roman world.
Membership on those terms was worth having as long as the empire itself was worth belonging to, and for two centuries it plainly was. The next lesson asks what paid for it, and finds that the answer changed early: after Augustus, the conquests stopped, and an empire that had always been funded by the next war had to learn to live on what peace produced.