How did Rome transform from republic to empire in Latin?

Question

I would like to understand how Rome transformed from republic to empire from the point of view of Latin language. I think I already have a sufficient understanding of Roman history to understand the political transformation, but I realized that I know almost nothing about how this transform was described by contemporaries in Latin.

When the Roman Republic become the Roman Empire, was there any change in how Romans referred to their country? An obvious first guess is that in the republic era it was called res publica Romana and later on imperium Romanum. However, it seems likely to me that res publica simply meant "state", republic or not, and imperium meant something like "command", "realm" or "authority". In this reading res publica Romana would mean the state of Rome from a political point of view and imperium Romanum the area under Rome's control. Evolving res publica and imperium into today's concepts of "republic" and "empire" can well be a later development.

To understand this issue, I would like to know an answer to these (interwoven) questions:

• What were the Roman Republic and the Roman Empire called in classical Latin when one wanted to make a distinction? My dictionary translates "republic" and "empire" as libera res publica and imperium, respectively, but I don't think this is the whole story.
• Did the way Romans referred to their state change when the republic became an empire?
• What did res publica Romana and imperium Romanum (and perhaps senatus populusque Romanus) exactly refer to? Was their use limited to some eras?
• Is there an ancient Latin text discussing a change in the name of the state due to the republic turning into an empire?

The transition was slow: the first stages of what we today know as the empire was seen as continuation of the republic. But the Romans must have realized that their republic was not the way it used to be before the principate turned into the dominate. I would like to know how the process was reflected in references to the state in the extant literature.

To answer this question, it is not necessary to answer every single question listed above — although I would be happy to see a thorough answer. I hope the list conveys the problem I want to have cleared up. Due to the somewhat broad nature of the question I want to explicitly encourage partial answers.

Answer 1

I don't think that you will find much in Latin during the period of change that discusses the transformation. There are clues to opinion, as you might expect, but the change was more accidental than deliberate — like so much in the preceding history. To deal with your second question from another standpoint, I'd like to offer a second, different kind of answer.

Even though there's a lot of available evidence (and it increases daily) for many aspects of life in the period best understood — say, a couple of hundred years or so from 146 BC — the mentality of the citizens inferior in status to the equestrian class is still hard to comprehend (and we learn little and slowly to improve on this). During that time, to the consternation of patrician traditionalists, new and corrupting religious practices were introduced to Rome. Marius changed public attitudes to the State by beginning recruitment from the lowest class. Settlements were reached with the Italian neighbours. Civil wars (especially that of AD 69) led to an influx of new blood to the governing class (as evidenced by the disappearance of old, and the rise of new names to public view). The system of governorships changed, and with it the titles used for them.

In all my years of studying the Romans I have constantly found that the more thoughtful commentators in modern times point to the same problem: that it is just about impossible to imagine the total reality of everyday life, almost anywhere in the Roman sphere of influence — let alone to deduce what went on in the citizens' minds about the system by which they were governed. Still the great prize of citizenship lay under everything, binding the true Roman to the Urbs, to his patria, whatever name he gave it. Originally, because it had depended on a peculiar, innate acceptance of the traditional Roman animist belief in their 'contract' with the gods (of consultation rather than worship), citizenship had been extended only grudgingly by the Republic to newcomers to Roman hegemony, but the attitude persisted: Juvenal, for instance, writes of the Orontes pouring its filth into the Tiber.

Was anyone in all this period able to say to himself something as concrete as 'the Republic is becoming an Imperial State'? Perhaps those in positions with power to impose such a change might; these would surely include Caesar, who recognised that the old system could not continue, and Vespasian, the non-patrician first to formally introduce the new order. Others would, I suppose, come to accept that monarchy was going to be the solution, anathema to a Roman as it remained: but not for many years, nor by any deliberate act, would the name Republic be discarded.

Answer 2

The distinction between ‘Republic’ and ‘Empire’ owes a great deal to convention among historians. When the Principate was first established by Augustus it did not, to the legalistic Roman mind, abolish the Republic, but merely continued it. Not until AD69 did it finally become clear that the reversion to rule by one man was irreversible, and at this point it was also apparent that military muscle was far more effective in appointing him than were the politicians.

After the death of Nero, the legionary commanders each commanded personal support, and the more ambitious made their bids for control. The eventual winner, Vespasian, was the first non-patrician ruler. Historians have given the title of Emperor to four of his predecessors, but only with Vespasian does it formally designate the new system of governance: a special definition of his powers passed into law for the purpose.

Thereafter it was customary to refer to the entire polity as an Empire, Imperium Romanum, and to each ruler as Emperor. The titles of ‘Augustus’ and ‘Caesar’ were given to the senior and junior rulers of the two halves of the Tetrarchy, first appointed (if that is the appropriate word) when the Empire split into eastern and western components in order to make more manageable. But it was still the ‘Roman Empire’ when Odoacer deposed Romulus Augustuls, the ‘last Emperor of the West’ in AD476, which left the East to become the Byzantine Empire.