This is a great question because different scholars have different perspectives about who was the first emperor of Rome. In order to appreciate the nuance of the debate, we’ll need to explore a little bit of Latin and the concept of “empire”.

Empire through conquest

Let’s start with the concept of a Roman empire. There are two important ideas to appreciate about empire that help us understand Rome and its politics. The first is empire as “domination over territory of peoples who are not Roman”.

Rome has a reputation as a war machine, gradually bringing the whole geographic region of Italy under its sway. Italy was populated by many different peoples and language groups from the Greek colonial outposts of Magna Grecia to the Etruscans to the Oscan speakers and more. In the ongoing struggle between cities and regions, Rome came to rule over all Italy. Rome expanded from there to annex states and cities further abroad.

Greece ends up under the thumb (214-146 BCE) and then Rome sets sight on the states of Asia Minor (roughly equivalent to the modern Middle East). Rome is also infamous for their victory in the Punic Wars with the destruction of Carthage (North Africa) in 146 BCE.

This control of geography and peoples who may not be Latin speakers is definitely what we would call “an empire created through conquest”. Rome is an established empire of this kind by around 264 BCE, when they put down an uprising in the Etruscan city of Volsinii.

Empire through politics

The second type of empire is a political structure, headed up by – drum roll please – an emperor. This is an extension of monarchy, but where a monarch rules over their own people as sovereign and is often the chief law-maker, an emperor rules over their own state and conquered states.

Does Julius Caesar fit the bill? Julius Caesar accrues vast military power which he parleys into political influence. This is where an appreciation for Latin can open up our understanding of the complexity at play in ancient Rome. As a military commander, one of the honours you can receive is acclamation as imperator. This usually comes from the soldiery, you can’t buy it (at least theoretically).

Julius Caesar is acclaimed imperator in 60 BCE by his troops in Hispania Ulterior (Plutarch, Life of Caesar 12):

[Caesar] had become wealthy himself, had enriched his soldiers from their campaigns, and had been saluted by them as Imperator

But what happens after that defines Caesar’s career and changes Rome itself. Caesar’s military exceptionalism in the 50s BCE translates into a controversial political sway with the crossing of the Rubicon. The Roman people were well aware of his military prowess, even if they disagreed with his methods. The loyalty of his troops was understood and it was difficult to prevent him from taking a leading role in the politics of the City.

Caesar’s informal power sharing arrangement with Pompey and Crassus (now referred to as the first triumvirate) breaks down with the death of Crassus in 53 BCE and Pompey in 48 BCE. He precipitates a civil war by marching on Rome with his army, and in the chaotic aftermath he accepts the title of dictator perpetuo: “dictator for life”.

Big side note: the position of dictator is usually reserved for emergencies and has the contingency built in of only lasting six months. A Roman dictator had one specific purpose, to return the City to a position of calm and order so proper governance could recommence with a new pair of consuls. But a dictator perpetuo flies in the face of the limited term and flirts dangerously with the type of political power despised in ancient Rome: the rex (king).

Rome’s uneasy relationship with monarchy and Caesar’s new role as what his enemies will call a de facto rex means there are some grounds for saying that he is Rome’s first emperor. It’s certainly true that Caesar ends up in a political position as the top dog while Rome rules over a whole bunch of places that aren’t Rome. But even so, the Romans didn’t necessarily see themselves as an empire of the second type while Caesar ruled. And this is very important.

In fact, the assassination of Caesar draws attention to the structures of government that have very little to do with having an emperor. Brutus, Cassius et al are interested in the continuation of the res publica (lit. “the public things”). They want to see a return to the two consul model – a Rome that is the first type of empire but definitely not the second. Rome isn’t ready to see itself as having an emperor just yet.

So if not Julius Caesar, who is the first emperor of Rome? There’s a few contenders depending on your persuasion:

Augustus

He also has the dubious honour of winning a civil war and reshapes Rome’s political structure enormously during his 40+ year career. He’s pretty firm the whole time that he’s all about restoring the republic (Res Gestae Divi Augusti 1), going so far as to make sure there’s always two consuls.

Toward the end of his life, Augustus was at pains to show his commitment to the Republic (Res Gestae Divi Augusti 34):

In my sixth and seventh consulates (28-27 BCE), after putting out the civil war, having obtained all things by universal consent, I handed over the state from my power to the dominion of the senate and Roman people. And for this merit of mine, by a senate decree, I was called Augustus and the doors of my temple were publicly clothed with laurel and a civic crown was fixed over my door and a gold shield placed in the Julian senate-house, and the inscription of that shield testified to the virtue, mercy, justice, and piety, for which the senate and Roman people gave it to me. After that time, I exceeded all in influence, but I had no greater power than the others who were colleagues with me in each magistracy.

But when you always get to speak first in the senate and there’s a third chair brought into senate meetings to sit between the consuls, things are looking very much like the second type of empire by the time Augustus really hits his stride after the 20s BCE. Would Rome agree it was an empire under Augustus? (Probably only in whispered corners, and then only by people willing to risk everything. Augustus can make you disappear.)

Tiberius

This is a man whose political career is polarising. Whether you are sympathetic to Tiberius or not, he does inherit a suite of powers from Augustus which makes him a pretty strong candidate to be Rome’s first emperor as far as we are concerned (Suetonius Tiberius 23-24 and Tacitus Annals 1.8).

Hereditary power is common in empires of the second kind and there’s no denying that Tiberius comes into his powers through Augustus’ will. Once these powers are confirmed by the senate, we’re looking at a crucial moment where Rome openly embodies both forms of empire: conquest, and political infrastructure. Now you might think we’re done and dusted there, but wait, there’s a third contender!

Vespasian

Sounds like a Johnny come Lately, but the Lex de imperio Vespasiani is probably the most concrete piece of evidence for the fact that Rome is now (in 69/70 CE) an empire of both kinds. This set of laws means that Rome has sealed the deal on the second kind of empire to supplement the first kind.

This law is very important because it openly allows a new imperial dynasty to have the legal grounds to operate. Vespasian comes to power after the tumultuous civil unrest following Nero’s suicide. With Nero’s death the Julio-Claudians were out, but how did power really work in Rome? The Lex de imperio Vespasiani cements the political structure of empire.

We can see this from the wording which makes Vespasian’s power the same as those key political powers who came before him:

“it shall be lawful for him to make a treaty with whom he wishes, just as it was lawful for the deified Augustus, for Tiberius Julius Caesar Augustus, and for Tiberius Claudius Caesar Augustus Germanicus…”

Notice how the first person to get a mention in this list is Augustus, not Julius Caesar, suggesting that the Romans themselves didn’t consider him an emperor.

Whoever you prefer from the list above, one thing is certain – Julius Caesar’s career reveals some imperial qualities, but it’s what happens after his death that really cements the heart of Roman politics as an empire.

For these reasons we rate this claim as mostly false.