Caesar’s Road to the Rubicon—Rome Goes to War

From the lecture series: A History of Ancient Rome

By Garrett G. Fagan, PhD, The Pennsylvania State University

With three large egos involved, it was inevitable that tensions within the triumvirate of Caesar, Pompey, and Crassus would rise. Yet how did the situation deteriorate so drastically that, when Caesar crossed a small river, known as the Rubicon, on January 10, 49 BC, it was akin to a declaration of war on Rome?

Image of the First Triumvirate of the Roman Republic
The First Triumvirate of the Roman Republic from left to right, Gnaeus Pompeius Magnus, Marcus Licinius Crassus, and Gaius Julius Caesar. (Image: By Mary Harrsch/Public domain)

In April of 56 BC, Caesar went down to the town of Luca, which was the closest town to the border of Italy. It was as far south as Caesar could go without relinquishing his proconsular power by leaving his province. Troops of senators went up to pay their respects. Pompey and Crassus were invited up to this conference. Caesar met with them, and the differences between the three men—the triumvirate—were patched up. Four important decisions came out of this conference.

Learn more about Rome’s great leaders from its beginning through the assassination of Julius Caesar and the reign of Octavian, Caesar Augustus

The Roman Republic on the Ropes

Marble bust of Gaius Julius Caesar dated 44 BC found at Tusculum , near Frascati.
Caesar extended his command in Gaul for five more years.

First of all, Caesar, who believed that his conquest of Gaul was still not entirely complete, had his command in Gaul extended for a further five years. As a balance, Pompey was given a command in Spain and Libya, giving him control over several legions there.

He was given a special dispensation that he could govern his provinces through representatives while he stayed in Rome. Pompey seemed to have enjoyed the high life of the city and did not fancy going off to Libya or Spain for long periods. He was not like Caesar, who enjoyed life on the campaign.

Bust of Pompey the Great Ma 6196 from the Louvre
Pompey was given command in Spain and Libya. (Image: Photographed by By Alphanidon/Public domain)

With Pompey in command in Spain and Libya and Caesar’s command extended, Crassus realized that he was being massively out shadowed by his peers and wanted some of the glory. His only real military success had been 14 years previously with the suppression of the Spartan rebellion, sullied by Pompey’s appearance.

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Crassus wanted military glory, and he was given a five-year command in Syria and the east. It was fully expected he would attack Rome’s only civilized neighbor in the east, the Parthian Empire, which he did.

Bust of Crassus in the Louvre Museum
Crassus was given a five-year command in Syria and the east. (Image: Photographed by cjh1452000/Public domain)

In addition, Crassus and Pompey were to be consuls in 55 BC to ensure that all these commands were properly voted through the various assemblies. It must be stressed that all of these decisions were made between the three men without reference to the Senate at all.

Essentially, they carved up the empire among themselves and then relied on violence and intimidation to ensure that their desires were met. The Roman Republic was on the ropes.

Caesar sent down some of his troops who were on furlough to “help” in the election of Pompey and Crassus for the consulship of 55 BC. Nevertheless, it was delayed because of virtual anarchy in Rome until the early part of January 55 BC. In due course, Pompey and Crassus become consuls and the various commands were doled out exactly as they were supposed to be.

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A Family Death and a Failed Invasion

If one were looking at the situation in 55 BC, one would think it looked like the triumvirate had been restored to power. But in fact, the years 54 to 49 BC saw the dissolution of the triumvirate and a civil war between Pompey and Caesar.

In the first place, in 54 BC, Julia, Caesar’s daughter and Pompey’s wife, died in childbirth. The marital link between Pompey and Caesar was thus broken, and it was not renewed.

Then, as proconsul in Syria, Crassus set off with great pomp and ceremony to attack the neighboring Parthian Empire in 53 BC. The Parthians had done nothing to deserve Crassus’s invasion; he simply attacked them for military glory. Crassus took his armies and 40,000 Roman infantry into the heartland of the Parthian kingdom.

Crassus, however, was completely incapable of dealing with the Parthian form of warfare, and his army was crushed at the Battle of Carrhae in 53 BC in northern Mesopotamia. Crassus himself, along with his son, was killed in battle.

The death of Marcus Licinius Crassus, by Lancelot Blondeel. Oil on panel, between 1548 and 1558. Groeningemuseum.
Carssus was killed during his invasion of the Parthian Empire in 53 BC. (Image: Photographed by Vassil/Public domain)

Pompey the Traditionalist, Caesar the Tyrant

Pompey and Caesar were left alone in their alleged alliance. The following year, in 52 BC, the situation in Rome became worse. Fighting between gang leaders, Clodius and Milo, basically blocked the government. Eventually, an enormous street fight just outside of Rome resulted in a fire in the Senate house that burned many parts of the city.

What followed was widespread disorder and rioting. In 52 BC, the Senate declared the ultimate decree, the senatus consultum ultimum, and appointed Pompey sole consul for the year to restore order, which he did by violence and force, bringing troops into the city. This sole consulship was unheard of and seems to have been a way to avoid creating an outright dictatorship.

By 52 BC, Pompey was aligned more closely with the Senate than he had been before. He had worked on its behalf to put down the violence that had besieged and disrupted the republic for so many years. A rather ominous event took place that year when Pompey married the daughter of a leading optimate senator, a man who was well-known to be an opponent of Caesar.

Pompey’s alliance with the conservative optimates seems to have gotten stronger. From 52 to 49 BC, the calls for Caesar’s recall from his proconsulship in Gaul and the prosecution of his behavior as a consul in 59 BC grew increasingly more strident.

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Pompey did nothing firmly to block these moves against Caesar, but he did not fully support them either. Pompey began to be convinced by the conservative elements in the Senate that he was the protector of the traditional way of Roman life, against the threat of Caesarian tyranny. Caesar wanted to come back from his proconsulship, of course, and take on a second consulship. Negotiations heated up as Caesar’s command in Gaul came to a close at the end of 50 BC.

The negotiations between Pompey, Caesar, and the Senate grew more intense. Caesar, it must be said in his favor, showed a high degree of reasonableness. In December of 50 BC, he made a final proposal that both he and Pompey disarm simultaneously. The Senate overwhelmingly voted in favor of this proposal, 370 votes for to 22 against.

“The Die is Cast”

"Crossing the Rubicon" from Abbott, Jacob, 1803-1879. History of Julius Caesar.
Caesar crosses the Rubicon. (Image: By Jacob Abbott/Public domain)

Even though the Senate had voted in favor of this proposal, the optimates prevailed on Pompey to mobilize to save the republic from the threat of Caesar’s tyranny. The situation could not have been clearer in Caesar’s mind. If he returned to Rome without his troops, with Pompey now mobilizing his troops, it would be the end of Caesar’s political career and possibly his life.

If, on the other hand, he entered Italy with arms, it would be declaring war on the Roman state. He brought his legions down to the border between Gaul and Italy to a small, unimportant stream called the Rubicon. He stared across the stream where Italia, his fatherland, patria, lay. He considered his options.

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He knew that if he brought his legions across, he would bring untold misery to massive numbers of people in what promised to be an enormous civil war. The entire resources of the Roman state arrayed against him. On the other hand, he wrote himself, his reputation in the state demanded that he not give in to his enemies, who were doing everything they could to see him humiliated and defeated.

After mulling over his options, he gave the order for his cavalry to advance, rode his horse across the stream under arms, and declared war on the state, we hear, with the phrase alia iacta est: “the die is cast.”

What happened next was a Roman world war that was to eventually see Caesar raised to the position of uncrowned king of the Roman state.

Common Questions About the Rubicon

Q: What does ‘cross the Rubicon’ mean?

The phrase ‘cross the Rubicon‘ refers to an act that cannot be taken back. Once done it cannot be undone.

Q: What were Caesar’s words when he was about to cross the Rubicon?

Julius Caesar spoke in Greek, quoting a play by Menander which said “let the die be cast.

Q: Why did Caesar cross the Rubicon?

Caesar crossed the Rubicon with his army to march on Rome and challenge the ruling bodies of the time in direct disregard for the law of the time.

Q: What does “the die is cast” mean?

When Caesar said “the die is cast,” he was quoting from a play by Menander meaning that what he was about to do cannot be undone. A die is a type of mold for making parts and when a die is cast, especially during Caesar’s time, it is usually done in metal and is thus permanent.

This article was updated on September 17, 2020

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