Eli5: Why was it world-changing that Caesar crossed the Rubicon?
In: 1397
It wasn’t world changing. It was a fairly big deal for the people who lived in Rome and its territories, and for some of the neighboring areas (like Egypt), but for most of the world it didn’t have any immediate effect.
Even within Rome, it wasn’t so much a sudden change as it was the culmination of a process that had already been going on for a couple of generations, in which powerful, popular generals would take over when things weren’t going their way. Caesar was just the first person in a while to take power and then refuse to give it up.
The major changes in Roman government don’t really happen until the transition from Republic to Empire, which did *not* happen under Julius Caesar. Caesar held the title of dictator, which had existed throughout the history of the republic. It was his adopted heir, Octavian (later Augustus) who began those changes.
Even then, though, I’d argue it wasn’t all that world-changing. The Empire didn’t really introduce a lot of novel ideas of governance. Some of the more competent Emperors expanded the territory and built some cool stuff, but some version of those things probably would have happened without JC crossing a river.
I’d say the biggest change brought about in the wake of Caesar taking power was that after the various civil wars Rome enjoyed a political stability that it might not have had if the Republic had continued, and which might have been necessary to keep the Roman political entity from blowing up.
Rome – the preeminent power in Europe – was at a crisis point. It was a Republic, and had been, for centuries. But it controlled France, Spain, Greece, Italy, and a lot of other territory. At the time there were two groups of people in Rome: Reformers (Caesar’s people who wanted to improve the common man and reform the republic) and the Conservatives (who liked how they had power). The Conservatives moved Caesar into a position where he would be tried and convicted of corruption. This would embarrass the Reformers, and Caesar had no desire to be embarrassed.
Caesar was a governor (kinda sorta), and immune from prosecution. His term as governor ended. He had a huge army. He crossed the Rubicon, defeated the Conservatives, and then secured his position for life. The Conservatives didn’t like that, so they killed him; this led to the end of the republic, and the creation of the Roman Empire; which eventually led to (1) Christianity’s dominance in the world; (2) Feudalism, the Middle Ages, and the eventual Renaissance that birthed our current world; and (3) the return of Republican thought as the Middle Ages [kinda sorta] ended.
It wasn’t world changing. He took an action that was irrevocable. When people use the idiom “to cross the rubicon” it has a similar meaning to “the cat is out of the bag” or “you can’t unring a bell”. When Ceasars crossed that river and brought his troops into Rome, he broke a sacred taboo and started a war whether he wanted to or not.
Some context: Rome at this time was controlled by the senate, a group of aristocratic elites. Since getting rid of their King, the senators developed a ‘crab in the bucket’ mentality, turning on any member who became too popular/powerful, lest they attempt to become King themselves.
At the time of the Rubicon, Caesar had just conquered Gaul (modern France), making him the richest and most famous politician in Rome. Also, Caesar was a populist, who was loved by the common masses. He also still had control of his battle hardened legions.
The Senate fearing Caesars growing power, declared him an enemy of the state, decreeing that he must disband his armies and turn himself into the Senate.
Caesar instead chose to invade Italy proper from Gaul with his army, the boundary being the river Rubicon. By crossing with his army, Caesar openly declared war on the Senate, starting another round of civil wars.
Crossing the Rubicon was the point of no return. Caesar is quoted; “The die is cast.”
When you are in Rome, you are a citizen. Citizens are not generals who command armies. The exception is during a triumph, when you have a military parade.
Crossing the river as a genera and not being a citizen is like a Roman invasion by an outside force.
“crossing the rubicon” is a phrase meaning you’ve fully committed to a course of action and there’s no going back.
its importance as a phrase is far greater than the actual event
There’s an entire [Netflix series dramatizing and retelling the history of Ceasar’s rise from soldier to emperor](https://www.netflix.com/us/title/80096545?s=a&trkid=13747225&t=cp&vlang=en&clip=81014090), so that will probably help clarify with historical context.
But first a few key points to understand the situation:
* Caesar was essentially “exiled” from the Roman Republic by Pompey “gifting” him with a governorship of any province he wanted (essentially forced retirement from politics in Rome itself by forcing Caesar to live in the boonies someplace), which forced Caesar to leave Rome and helped eliminate the threat Pompey felt from Caesar.
* Caesar chose to become governor of a border territory, then took it upon himself to amass an army and start conquering territory and he was so successful that he wound up conquering all of Gaul (modern France) and became massively popular and celebrated in Rome as a direct result of his conquests, stories, and the plunder he sent back to Rome.
* Pompey raised a stink and said that Caesar had committed the crime of raising an army and going to war without the prior approval of the Senate, he demanded that Caesar surrender himself so that he could stand trial for his crimes for which he would likely be found guilty because Pompey had the support of the Senate to convict.
At this point Caesar had a choice to make. He could either:
1. Surrender himself, stand trial, and likely be executed as an enemy of the Republic because the senators had vendettas against him and saw him as a major threat.
2. He could march his army to Rome, technically an act of war against the Republic, and see if he could negotiate, cajole, or fight his way to a resolution.
He chose #2 and in doing so went to war against the Roman Republic (the Senate) and after a long series of events returned to Rome to claim the title of “Dictator” effectively ending the Republic and beginning the Empire.
It was “world changing” because that decision to cross the Rubicon was the moment where Caesar sealed the fate of the Republic and began the long, bloody, and tragic history of Roman Emperors who would wield absolute power over their massive empire in all kinds of ways that impacted the lives of people all over the world.
It wasn’t world-changing, it was **Rome-changing**. And it wasn’t even that unprecedented, since Sulla had done the same thing 31 years before, only he took the side of the Optimates (the rich people). Caesar took the side of the Populares, the poor people, and the rich Senators assassinated him.
Tons of great extensive answers but here is the eli5;tl;dr
In the roman republic, soldiers where not allowed in the city, unless you had a special permit. This was to separate the military from the politics.
The Rubicon was the entrance to the old city, so when Caesar crosses the Rubicon he is breaking the law and declaring war against the roman republic.
There are loads of great answers already detailing the pop culture understanding of the term (ie julius Caesar crossing the river with his army amounted to a declaration of war, a step beyond which it was impossible to turn back).
However! TIL that this isn’t actually true.
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byu/RusticBohemian from discussion
inAskHistorians
tl;dr – The Senate was the aggressor, not Julius. They forced his hand by repeatedly attempting to strip him of his power, illegally removed his allies from the senate, etc.
The “crossing the Rubicon” idea came from a poem written 100 years after the event, and probably had no particular significance to the people of Julius’ time.
(So… it’s essentially a pop culture meme of its day, rather than “real history”?)
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