The Roman Empire was governed for three centuries by a position that had no legal existence, and the man who invented it spent forty years making sure nobody had to say so out loud.
This course begins where the course on the Republic ends: with Octavian, renamed Augustus in January 27 BC, holding every army and claiming to have handed the state back to the Senate and people. The question here is not whether the Republic was really restored, which it was not, but what was built in its place, because the thing built in the 20s BC is what governed sixty million people until the third century broke it. If you have not read the earlier course, all you need is this: the Republic was an aristocracy of annual elected magistrates that could not control the generals its empire required, and it destroyed itself in a century of civil war that Augustus ended by winning.
Powers, not a throne
Start with what Augustus actually held, because the list is more surprising than any summary of it.
From 31 to 23 BC he was consul every year, which was legal but conspicuous, since it meant one of the two annual places was permanently occupied. In 23 BC he gave that up and took two things instead. The first was tribunicia potestas, the power of a tribune of the plebs without the office: the right to propose laws to the assembly, to veto any magistrate, and personal sacrosanctity, held for life and renewed annually so that it could be counted. He counted it for thirty-seven years, and imperial documents dated themselves by it for the next four hundred. The second was proconsular imperium, held permanently, not lapsing when he entered the city as a proconsul's normally did, and outranking that of any other governor.
To these were added the office of pontifex maximus in 12 BC, when the previous holder finally died, and the honorific pater patriae in 2 BC. He was consul thirteen times in all, and he took no office that had not existed in the Republic.
That is the whole legal basis of the Roman Empire. There is no law creating the emperorship, no coronation, no regalia, and for a long time no agreed word: princeps, meaning the leading man, was a term of respect the Republic had used of senior senators; imperator, which he turned into a first name, meant a victorious general; Augustus was a religious adjective with no political content at all, which was exactly its merit.
Example. Every element in that list existed under the Republic. What was new?
The combination, and its duration. A tribune's veto, a proconsul's command and a chief priesthood were all ordinary republican things, and the Republic's protection against them was that each was held briefly, by an elected man, alongside a colleague with equal power. Augustus removed the brevity, removed the colleague where it mattered, and kept the names. Notice also which two he chose. Tribunician power gave him a permanent legal presence inside the city without a magistracy, and proconsular imperium gave him the armies. Between them they cover the two things that had decided every political dispute since 133 BC: control of the streets and control of the legions. The genius is not in inventing anything, since he invented nothing. It is in having noticed exactly which republican instruments were load-bearing.
Now you. Why did he never take the dictatorship, which the people offered him in 22 BC during a famine, and which would have been simpler?
Answer
Because his adoptive father had held it and been stabbed to death for it, and Augustus watched that happen at eighteen. The dictatorship was a real republican office with a real precedent, and both were poisoned: Sulla's proscriptions and Caesar's dictatorship for life had made the word mean permanent personal rule. Suetonius says Augustus went down on his knees, tore his toga from his shoulder and begged the crowd not to force it on him, which is a piece of political theatre that tells you the refusal was the point. He preferred a set of unobjectionable powers with an aggregate effect that nobody could name to a single office with a name everyone understood. The rule he was following applies well beyond Rome: what a regime is called is often more dangerous to it than what it does.
The Res Gestae, and how to read it
Augustus wrote his own account of his reign, the Res Gestae Divi Augusti, a document of thirty-five short chapters, and had it inscribed on bronze pillars at his mausoleum. The bronze is long gone. What survives is a copy cut into the wall of a temple in Ankara, with fragments from two other towns in the same province, which is why a text written for the city of Rome is known from central Anatolia.
It is the most useful document in Roman history and one of the least trustworthy, and both for the same reason: it is a monarch's own statement of what he wished his reign to be understood as, in his own numbers. It is full of exact figures, and they are the interesting part. He lists the cash he gave the plebs, the number of citizens in each census, the veterans he settled, the gladiators shown, the temples repaired (eighty-two in one year), the number of times the temple of Janus was closed to signify peace throughout the empire (three, against twice in all previous Roman history).
What it never mentions is a defeat, a rival, a proscription, a name of any opponent, or the words for the powers it describes. Mark Antony appears only as an unnamed faction. The reader is told the sums spent on the treasury and the army and never told that the man spending them owned Egypt.
The household that became a government
The Republic had almost no state apparatus, and Augustus did not build one either. What he did was staff the empire's new jobs from his own house.
Egypt, taken in 30 BC, was not given to a senatorial governor. It was administered by a prefect of equestrian rank, a man of the second order who could not raise a rival claim, and no senator could set foot in the province without the emperor's permission. Rome itself got a prefect of the city with three urban cohorts, a prefect of the grain supply, and in AD 6 a corps of seven cohorts of vigiles, watchmen who fought fires and patrolled at night, all of them equestrian commands answering to the emperor. The praetorian guard, nine cohorts of them, was created as a standing bodyguard under two prefects, also equestrians.
Below that level the work was done by the emperor's freedmen and slaves, running correspondence, petitions and accounts out of what was formally a private household. The imperial finances themselves were never fully separated from the man: the state treasury, the aerarium, continued under the Senate, while the emperor disposed of provincial revenues, his own vast private estates, and Egypt, which he held as personal property.
Paying the soldiers, permanently
The one genuinely new institution of the reign is the least glamorous, and the earlier course explains why it was needed: since Marius, soldiers without property had depended on their general to obtain land at discharge, which is what made armies personal.
In AD 6 Augustus set up the aerarium militare, a military treasury, endowed with 170 million sesterces of his own money and funded thereafter by two new taxes on Roman citizens: five per cent on inheritances and one per cent on goods sold at auction. Service was fixed at twenty years, and the discharge payment at 12,000 sesterces.
Example. Work out roughly what that fund had to pay each year, and say what the arithmetic implies.
Twenty-eight legions of about 5,000 men is 140,000 legionaries. With twenty-year terms, a steady state discharges about one twentieth of them annually, or 7,000 men, and at 12,000 sesterces each that is 84 million sesterces a year, before the auxiliaries are counted. The emperor's 170 million endowment covers two years of it. So the gift is a founding gesture and the taxes are the institution, which is why he was willing to be the first Roman ruler to tax Roman citizens directly since 167 BC and to take the unpopularity of doing it. The point is worth holding on to for the rest of this course: the empire's central fiscal problem, from Augustus to the fifth century, is that soldiers have to be paid on time by somebody other than their commander.
Now you. The legionary's pay was 900 sesterces a year. What does a 12,000 sesterce discharge bounty represent, and why set it that high?
Answer
Thirteen and a third years of pay, arriving in one payment at about forty years of age. It is a pension in the form of a lump sum, and it is large enough to buy a modest farm, which is precisely the point: it replaces the land that a general used to have to extract from the Senate for his veterans. Look at what that does to loyalty. A soldier who serves twenty years for a state that will pay him at the end has an interest in the state surviving those twenty years, and no reason to follow a commander into a civil war that might cost him the payment. That is the mechanism Augustus was buying, and it worked for fifty years. It also creates a permanent obligation which the state has to meet in cash, which is why every emperor in this course is, among other things, a man worrying about revenue.
What the empire bought with it
It is easy to describe the principate as a confidence trick and stop there. The two centuries that followed suggest something was actually delivered.
The civil wars stopped. Between 31 BC and AD 68 no Roman army fought another in Italy, after a century in which that had happened in every generation. Piracy stayed suppressed, the grain came in, and a common coinage made the Mediterranean a single market to a degree it would not reach again for a very long time. Provincials, who had been the property of whichever governor drew the lot, got an appeal to somebody above him.
Tacitus, no friend of the system, gives the mechanism in one sentence at the start of the Annals: Augustus seduced the soldiers with bonuses, the people with cheap grain, and everybody with the sweetness of peace. It is meant as an indictment and reads equally well as a description of a functioning government.
The one thing he could not build
Which brings us to the flaw, and it is structural rather than personal.
If the principate is not an office, it cannot be filled. There is no election for it, no law of succession, no procedure of any kind, because admitting that a procedure was needed would have admitted that the thing existed. What Augustus did instead was to build an heir, by marriage and adoption, and to have him voted the same powers in the old man's lifetime so that the transfer would look like continuity.
He tried for forty years. His nephew and son-in-law Marcellus died in 23 BC. His friend, general and son-in-law Agrippa died in 12 BC. His grandsons Lucius and Gaius, whom he had adopted as sons, died in AD 2 and AD 4. Only then, at sixty-six, did he adopt his stepson Tiberius, a man he did not much like, and require Tiberius in turn to adopt Germanicus. When Augustus died at Nola in August AD 14, aged seventy-five, Tiberius already held tribunician power and an imperium equal to his, and the succession still had to be staged in the Senate as a piece of theatre in which the heir declined and the senators insisted.
Example. Tacitus reports that at the first meeting of the Senate after the death, Tiberius asked the senators to define which part of the state's business he should undertake, and they refused to answer. What was the difficulty?
That nobody had a vocabulary for the transaction, and both sides knew it. The senators could not offer him a position that did not officially exist, and to name it would be to admit that Rome had a monarchy and that they were voting for it. Tiberius could not simply take it without confessing the same thing. So the meeting consisted of a man asking for something he could not describe from a body that could not grant it, and it ended with the powers being conferred anyway. That is what a constitution looks like when its central institution is unmentionable. It also explains why the accession of every subsequent emperor is improvised, and why the improvisations get worse.
Now you. Suetonius says that on his last day Augustus asked his friends whether he had played his part well in the comedy of life, and asked them to applaud as he left. What claim is being made?
Answer
That the whole thing was a performance, and that he knew it, and that its success is to be judged as a performance is judged, by whether the audience accepted it. Take it as a story rather than a transcript, since Suetonius wrote a century later and death-bed lines are the least reliable genre in ancient biography. Its value is that it is exactly the anecdote a Roman of the next century found convincing about Augustus, which tells you how the reign was understood by the people who lived under its results: not as a restoration and not as a tyranny, but as a very long and very skilful act that everyone agreed to watch. The trouble with an act is that the next performer has to be as good, and there was no audition.
Where this leaves the empire
Augustus left a state with a professional army, a working revenue, a governed Mediterranean and a ruler whose position was undefined and therefore untransferable by any rule.
For fifty-four years the problem was concealed by family. Tiberius, Caligula, Claudius and Nero were all descended from or married into the same house, and the fiction of continuity held because a Julio-Claudian was always available. The next lesson is about what happened when there was not one, and about the discovery that Tacitus says the year AD 69 let out of the bag: that emperors could be made somewhere other than Rome, by people other than senators.