“He [Caesar] himself spent the day in public, attending and watching the exercises of gladiators; but a little before evening he bathed and dressed and went into the banqueting hall. Here he held brief converse with those who had been invited to supper, and just as it was getting dark and went away, after addressing courteously most of his guests and bidding them await his return. To a few of his friends, however, he had previously given directions to follow him, not all by the same route, but some by one way and some by another. He himself mounted one of his hired carts and drove at first along another road, then turned towards Ariminum. When he came to the river which separates Cisalpine Gaul from the rest of Italy (it is called the Rubicon), and began to reflect, now that he drew nearer to the fearful step and was agitated by the magnitude of his ventures, he checked his speed. Then, halting in his course, he communed with himself a long time in silence as his resolution wavered back and forth, and his purpose then suffered change after change. For a long time, too, he discussed his perplexities with his friends who were present, among whom was Asinius Pollio, estimating the great evils for all mankind which would follow their passage of the river, and the wide fame of it which they would leave to posterity. But finally, with a sort of passion, as if abandoning calculation and casting himself upon the future, and uttering the phrase with which men usually prelude their plunge into desperate and daring fortunes, "Let the die be cast," he hastened to cross the river; and going at full speed now for the rest of the time, before daybreak he dashed into Ariminum and took possession of it.”
Plutarchos - Βίοι Παράλληλο (Parallel lives) Caesar XXXII. 4-8
The Rubicon was a relatively minor waterway in northern Italy. It wasn't even very wide. It could easily be crossed on foot by Roman legionaries, slaves, generals, and whoever else might be traveling with a Roman army. But since ancient times, the Rubicon River had marked the northernmost boundary of Rome proper. No Roman general could cross it while at the head of his army as that would be considered treason. Treason was punishable by death. Someone who committed treason would inevitably be hunted down by Roman soldiers and dragged to the Roman Senate, where he would be tried, with the very likely outcome being a guilty verdict and a death sentence.
This day, 2062 years ago, in 49 BC, Julius Caesar did exactly what was deemed illegal, crossing the Rubicon with a legion of his soldiers. Specifically, Governors of Roman provinces (promagistrates) were not allowed to bring any part of their army within Italy itself and, if they tried, they automatically forfeited their right to rule, even in their own province. So, this act of leading his troops into Italy would have meant Caesar’s execution and the execution of any soldier who followed him, had he failed in his conquest.
So, why Julius Caesar decided to take the risk, break the most sacred laws of Roman Empire, and put his life and life of his soldiers under mortal danger? Let’s get back to the historical background.
After Caesar spent 51 BC and the better part of 50 BC touring his newly conquered province of Gaul, political chaos was developing back in Rome. The optimates despised Caesar and his conquests (viewing much of his campaigning as unwarranted and illegal) and looked for every opportunity to strip him of his command. These conquests not only brought in a great number of slaves, but brought so much monetary wealth into Rome, that the value of gold was actually reduced by as much as 1/4 or even 1/3 of its value before the wars. However, that was only one small piece of the puzzle as Caesar managed to make numerous powerful enemies in Rome. Caesar's original Consulship in 59 BC was one in which he not only acted against the central power interests, but openly opposed to the law and political custom. Such actions were destabilizing and dangerous for the health of the Republican system.
Therefore, the government in Rome was looking for mere opportunity to prosecute Caesar for a variety of reasons, including conducting an illegal war into Germania that the Senate never authorized. In fact, many argued that the protection of Cisalpine Gaul and Narbonensis didn't require the war that Caesar conducted in the larger part of Gaul in the first place. Prosecuting Caesar, whether the goal was death, exile or just a symbolic limitation of his power, would prevent his re-establishment of the populares agenda that he so masterfully manipulated previously. The years 50 and 49 BC were pivotal because during this time frame, Caesar's 'imperium' or safety from prosecution was set to expire.
So, Caesar was actually took a great risk and put himself in danger, but the point is that he was in danger already, and he preferred military fight to the legal battles in Rome, where his positions were much weaker than of his opponents. So, his options were to lay down his imperium and get buried by his enemies in Rome or to march on Rome with his troops and take the place over. He chose the latter, and not without precedent, Sulla having done much the same a couple of decades earlier.
Caesar at the Rubicon
According to the historian Suetonius, Caesar wasn’t at first sure whether he’d bring his soldiers with him or come quietly, but he ultimately made the decision to march on Rome.
Caesar stood for some time upon the banks of the stream, musing upon the greatness of the undertaking in which simply passing across it would involve him. His officers stood by his side. "We can retreat now" said he, "but once across that river and we must go on." He paused for some time, conscious of the vast importance of the decision, though he thought only, doubtless, of its consequences to himself. Taking the step which was now before him would necessarily end either in his realizing the loftiest aspirations of his ambition, or in his utter and irreparable ruin. There were vast public interests, too, at stake, of which, however he probably thought but little. It proved, in the end, that the history of the whole Roman world, for several centuries, was depending upon the manner in which the question new in Caesar's mind should turn.
First testing the loyalty of his men, (he only had the 13th legion with him at this point) he gave a stirring speech pointing out the wrongs done to him (and the tribunes). With the clear support of his men Caesar added, "Even yet we may draw back; but once across that little bridge, and the whole issue is with the sword." He is then reported to have muttered the now infamous phrase, from the work of the poet Menander, "Alea iacta est", quoted as "Let the die be cast" or "Let the dice fly high."
“The soldiers of the thirteenth legion, who were present, and whom he had sent for in the beginning of the troubles, (the rest not being yet arrived,) cried out, that they were determined to maintain the honour of their general, and to revenge the wrongs done to the tribunes.” (Caesar - Commentarii de Bello Civili I.7)
As soon as the bridge was crossed, Caesar called an assembly of his troops, and, with signs of great excitement and agitation, made an address to them on the magnitude of the crisis through which they were passing. He showed them how entirely he was in their power; he urged them, by the most eloquent appeals, to stand by him, faithful and true, promising them the most ample rewards when he should have attained the object at which he aimed. The soldiers responded to this appeal with promises of the most unwavering fidelity.
End of Republic
Shortly after the news hit Rome that Caesar was coming with an army, many of the Senators, along with the consuls G. Claudius Marcellus and L. Cornelius Lentulus Crus, and Gnaeus Pompeius Magnus, a.k.a. Pompey (Caesar’s chief rival for power who was supporting the Senate), fled Rome. Somewhat humorously, they were under the impression that Caesar was bringing nearly his whole army to Rome. Instead, he was just bringing one legion, which was largely outnumbered by the forces Pompey and his allies had at their disposal. Never-the-less, they fled and after a four year struggle, Caesar was victorious and Pompey fled to Egypt where he was assassinated. Caesar then became Dictator Perpetuus of Rome. This appointment and changes within the government that happened in the aftermath ultimately led to the end of the Roman Republic and the beginning of the Roman Empire.
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