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Crossing The Rubicon, Literally – Caesar Sparks War In 49 BC

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Brave, cunning, inspiring, and charismatic – by rights, Julius Caesar should have been the most glorious political celebrity in Rome.

Said to have wept with envy over a statue of Alexander the Great, Caesar burned with ambition and had saddled politics and the military in his efforts to emulate his idol.

As a military governor and general, he’d defended Roman lands from barbarian attack, and expanded those lands further into Europe, advancing his own career and reputation in the process.

Alexander the Great
Likeness of Alexander the Great, held at Ny Carlsberg Glyptotek, Copenhagen (image: Carole Raddato)

Venturing as far as Britain, his main stomping ground was northern Italy and Gaul, a territory spanning a little beyond the borders of modern France, where he’d fought many a brave battle.

One example is when he’d courageously rallied troops marching along the ancient road at the Sabis river (the Sambre).

Ferocious tribesmen had burst out of the woods on either side and rushed his legionnaires in a mass ambush.

Nic Fields says in his book 'Julius Caesar' that the general grabbed a shield, stood amongst his troops, and directed the battle while embedded within it. Soon, his patient, well-drilled troops carried the day:

“The Gauls fought in war bands that were fragile… They were almost as much in competition with each other for glory as… with the foe… Roman discipline, on the other hand, demanded doggedness… and a good organization… the exhausting method of powerful strokes employed by the Gauls, albeit red-blooded and strongly limbed, would not last long against the… less fatiguing method of swordplay utilizing the (skillful thrust of the Roman soldier)”.

In the ancient world, the Romans were distinguished by supreme order and discipline, particularly in battle - something Caesar used to maximum advantage.

The emblem of the army: "Senātus Populus que Rōmānus", 'the Senate and the People of Rome' (image: Sonarpulse)

The main building block of the Roman army was the legion, to which its soldiers loyally adhered as they paraded, trained, feasted, and celebrated together.

Somewhere between a division and a brigade, this roughly 4,800-man formation was subdivided into 10 480-soldier cohorts, while each of these contained six centuries with 80 men each. 

Centuries and their section-sized contubernium were where a legionnaire would form even greater bonds of loyalty and attachment to his comrades and the units to which they all belonged.

Each man, in Caesar’s day, could be expected to serve for six years, although this was later expanded to up to 25.

Raw recruits ranged in age from 17 to 36, and men up to the age of 46 were liable for military service if needed.

Ideally, a given soldier would be of rugged country stock and 5’9” or more.

Though elite units mandating men be at least 5’7”, and archaeological finds of soldiers ranging from 5’5” to 6’2” show that this was only an ideal candidate.

Basic training fused men together over a four-month process of marching, 29 km in five hours at regular step and 35 km at a faster one, all while loaded with a training pack of 20.5 kg.

Their real equipment weighed more and consisted of armour (including a helmet), a heavy shield, Roman sword, and a pilum - a javelin or throwing spear.

The testudo, or 'tortoise' (image: Dun.can)

With these, soldiers would be drilled endlessly, attacking 6 ft posts, and forming hollow squares, wedges, circles, and the testudo.

Ross Cowan’s 'Roman Legionary 58 BC – AD 69' describes this as “a mobile formation entirely protected by a roof and walls of shields”.

He also says:

“They were trained in overcoming obstacles, in charging and breaking off combat, in changing lines and relieving engaged units. The recruit was also taught to spring out of the line – this might prove useful in combat”.

The ranks also frequently incorporated or trained men as engineers, something that came in handy for Caesar in another of his famous battles, the siege of Alesia in 52 BC.

Battle of Alesia from Ancient Warfare issue VI-6 © Karwansaray Publishers Jose Cabrera Pena
The Battle of Alesia (image from 'Ancient Warfare' issue VI-6 © Karwansaray Publishers Jose Cabrera Pena)

Gaulish resistance to Roman occupation and incursion centred on a man named Vercingetorix, whom Caesar chased to and besieged on a fortified hill.

He was then in turn besieged by Gaulish reinforcements. 60,000 legionnaires were pitted against somewhere between 180,000 and 330,000 ‘barbarians’.

But the Gauls were divided and would be conquered.

Vercingetorix’s 80,000 men were hemmed in and starved out by a wooden fortress Caesar’s men had flung up with both speed and lethal precision – it was surrounded with trenches, stakes, and booby-trapped pits housing spikes.

Meanwhile, the outward facing ring kept Vercingetorix’s allies at bay, and when they struck at what they thought was a weak point in the fortress, Roman cavalry surrounded and cut them down.

The remaining forces were soon dispatched in turn, leaving the core of resistance without any chance of resupply. 

Ancient Roman history
Vercingetorix (on horseback) surrenders to Caesar

Vercingetorix was taken prisoner, and years later paraded through the streets of Rome before being executed by strangulation.

It was surely the crowning achievement in a long campaign utilising Caesar’s combined military and political genius.

According to Fields:

“During his campaigns in Gaul his manner of waging warfare was to conquer either by physical violence or by psychological persuasion. War then as now was Janus-faced: fight a war of the mind as much as a war of blood and iron; pay off the passive; pacify the proud”.

(Janus was the Roman god of time and transition, said to be two-faced because he looked into the past and the future simultaneously).

Both externally and internally, the whole of Roman political and military architecture was built on optimising carrot and stick.

On the one hand, cowardice or dereliction of duty would be punished by demotions, floggings, or even being beaten to death by one’s comrades.

Decimation, the random selection of one man in ten for execution if an entire unit failed to live up to standards, was also employed.

Softer punishments might be more boring (‘detested barley’) rations, ostracising through isolated encampment, the stripping of honours, or parading in heavy armour and in a stress position, holding heavy staffs or loads of turf on outstretched arms.

On the other hand, glory and prestige were the end result for loyal, dutiful legionnaires, and because of his inspiring physical courage, Caesar’s men are thought to have been particularly devoted.

So to the beaten ‘barbarian’ hordes, Rome must have looked like a lethally efficient conquering machine.

But in reality, it was internally fragile, and its greatest weapon, the army, was actually part of the problem.

In Caesar’s time, Rome was an established republic and former monarchy, and like modern democracies was politically arranged to limit power.

The engine of government was the 600-member Senate, which was headed by two alternating consuls serving a one-year cycle between them.

Any public office, by a combination of law and convention, was not meant to be filled by the same individual for more than one term (though in practice, this did sometimes happen, though very rarely in the case of the consulship).

The Roman senate
The Roman Senate

But while the Romans were sceptical, or even fearful, of concentrated political power, they had a huge blind spot for the danger posed by private wealth.

This found its way into, and was increased by, the affairs of the Roman state. In time, the republic would succumb to the danger commonly faced by democracies throughout history, and in our own time: Oligarchy.

Their society became increasingly bifurcated, with the patrician class at the top, manoeuvring in political races to get the most votes from the plebeians at the bottom.

Senatorial contests were not set up to debate different policy ideas because, while cliques and alliances naturally formed, there were no overt parties.

This reduced elections to personality contests in which, according to Adrian Goldsworthy in 'Caesar’s Civil War 49 – 44 BC', political aspirants would have to win favour with the ‘plebs’:

“Each aristocrat… tried to represent himself as a capable man, ready to cope with whatever task the Republic required of him, be it leading an army or building an aqueduct. Men paraded their past achievements and – since often before election they personally had done little – the achievements of past generations of their family”.

While today’s politicians try to incentivise voters with promises of certain policies, services, jobs programs, or tax cuts, Rome’s senatorial candidates went bigger:

“Vast sums of money were lavished on the electorate, especially in the form of games, gladiator shows, feasts and the building of great monuments. This gave great advantages to a small core of established and exceptionally wealthy families”.

And naturally, the higher the office, the more financially taxing it was to get there, meaning that most senators, while wealthy, still weren’t able to marshal enough resources to win the consulship – much like US congressional versus presidential races today.

Gladiator contests were a huge part of the spectacle of Roman entertainment

Perversely, there was also no check on the conflict of interest posed by a consul commanding his armies in war, and profiting from their booty (including slaves) afterwards.

Rome was civilised, elegant, glorious… and corrupt, nepotistic, and barbarous. Its hybrid republican-plutocracy was also making it increasingly dangerous to itself as it began to fracture and militarise. 

Foreign conquests had incorporated land and wealth into Rome’s territory while disproportionately enriching the patricians, and particularly a small number of families.

But gobbling up more lands required an increasingly professionalised and stoic army to garrison it for long stretches. What would their rewards be?

Some, Caesar included, promised chunks of foreign territories to former legionnaires.

This made him look vastly better than many in the government, out of touch as they were with the humble origins of many a soldier.

Caesar on the Rubicon
Caesar about to cross the Rubicon (image from 'Julius Caesar' by Nic Fields © Osprey Publishing, part of Bloomsbury Publishing)

So on the night of January 10 - 11, 49 BC, as he stood on the northern bank of the Rubicon river weighing his options, Caesar knew he could count on the loyal XIII Legion that was with him.

He would need them - Caesar had made many enemies. 10 years before, he’d formed the First Triumvirate with Pompey Magnus (‘the Great’), and Licinius Crassus, essentially a wealthy property mogul.

At the time, Caesar had been the junior member, at first advancing the trio’s agenda through Crassus’ vast wealth, and Pompey’s military reputation, while cementing the bond with a marriage between the latter and his own daughter.

They’d managed to bring a coherence and unity to senate affairs while advancing their own agendas together.

Many years later, after years as an adventuring military governor, Caesar’s reputation had come to rival Pompey’s, while Crassus had died at war years before.

Now the damage done by Caesar's support for Publius Clodius in Rome, the radical politician who’d intimidated senators with thugs, was coming back to haunt him.

As was the death of his daughter during childbirth, twisting Pompey in his intense grief away from Caesar, and towards his opponents who were united in their growing fear and resentment of him.

Because of the principle of limited power, military and political high office were not meant to be held at the same time.

If Caesar crossed the Rubicon with his army that night, civil war would be assured on January 11. 

But how could a man who adored and lusted after the kind of reputation enjoyed by Alexander the Great abandon the power and prestige he’d spent years building?

Equally, how could he stay on in a dead-end position as a mere provincial military governor/general?

Less cynically, some historians have pointed out that Caesar was locked into a ferocious dispute with the establishment that might have resulted in legal prosecution, or worse.

Historian Thomas R Martin, of the College of the Holy Cross, describes his dilemma thus:

“Caesar knows that if he were to disband his army and come to Rome, he would be murdered by his rivals, who hate his success, and know that Caesar can’t be stopped because he’s so popular. So Caesar’s life was literally on the line”.

No, the XIII would be there to protect him, even if it did trigger war.

While his opponents had every cause to throw the rule book at Caesar, it was they who fled in the face of his advance.

They may have been on the high ground politically, but they were not militarily.

Disorganised and outmatched, they regrouped under Pompey’s banner and the war for the future of Rome began.

There would be a number of battles in which Caesar prevailed.

Since both sides were Roman, and essentially identical, this is said to indicate better generalship by Caesar, though the fact that his forces were battle hardened veterans and Pompey’s were not must have been pivotal. 

At Pharsalus, in Greece, in 48 BC, Caesar was outnumbered, his foot soldiers ranged against Pompey’s.

But even the latter’s numerically superior cavalry, foreign, and lacking Roman discipline, was caught off guard by their enemies.

With a ratio of seven to one, they overwhelmed Caesar’s cavalry, but quickly lost formation and momentum.

Seizing the opportunity, reserve infantry hiding behind the main troop body sprung on them and cut them down.

Next, the infantry closed with Pompey’s men, rolling up his line and herding them towards the Enipeus River on their right flank.

Battle of Pharsalus
The front line at Pharsalus (image from 'Pharsalus 48 BC' by Si Sheppard © Osprey Publishing, part of Bloomsbury Publishing)

Pompey fled the scene, having lost 15,000 dead, and 24,000 prisoners to Caesar’s mere 200 (figures are often taken from Caesar himself, and thought to not be reliable).

Magnanimous in victory, former enemies were quickly pardoned, including Brutus, the young senator inspired to enter politics by Caesar.

He may well have also been his illegitimate child (Brutus’ mother was Caesar’s former lover).

At Thapsus in 46 BC, and Munda in 45, Caesar would go on to defeat Pompey’s sons, launching surprise assaults to down war elephants, and then rallying his men for one final battle by charging out in front of them at the enemy.

Nic Fields says the entire army followed, “constantly winning and losing advantage in different parts of the field, until at evening they just managed to secure victory”. 

It was a brutal slog. One veteran who met Caesar in Rome afterwards reputedly told him:

“I am not surprised that you do not recognize me. The last time we met I was whole, but at Munda my eye was gouged out, and my skull smashed in”.

Caesar would now become king of Rome in everything but name, his main rival Pompey having escaped to Egypt after Pharsalus.

He was betrayed and murdered, his decapitated head ferried to Caesar in a basket.  

Victory though, would bring new problems for Caesar. Up to 60 conspirators sneaked knives into the senate on March 15, 44 BC, and surrounded and then stabbed Caesar 23 times.

Accounts of his last gasp vary, but, upon realising that Brutus was one of the assassins (he was actually the co-leader), Caesar is said to have either pulled his toga over his head, or uttered in Greek:

“Kai su, teknon?” (“You too, child?”)

In the end, Caesar had emulated Alexander the Great, though not perhaps in the way he’d intended.

Both were assassinated (Alexander is thought to have been poisoned) after accumulating great power through military conquest, the fallout of which would lead to more military conflict.

Rome itself had expanded by force into kingdoms left over from Alexander’s empire, and would also be torn apart by another civil war.

While the greatness of the Caesar brand was imitated and echoed throughout history, being the basis for the Russian word for emperor, “czar”, and the German for king, “kaisar”, genetically his line would come to rule again in Rome.

After defeating Caesar’s rivals, the Second Triumvirate, like the first, would also break apart as its members turned on each other. 

Mark Anthony, Caesar’s former lieutenant who had succeeded him in bedding Egypt’s glamorous ruler Cleopatra, was defeated along with her in a naval engagement at Actium in Greece, in 31 BC.

The pair committed suicide, leaving Caesar’s maternal great-nephew and adopted son and heir Octavian to become Augustus, the first emperor of Rome, ending the republic. As Thomas Martin says:

“Long term, the infusion of obscene riches into Roman politics, the turning of the army into clients of the general as a patron, and the intense rivalry among the aristocrats to defeat each other instead of serving the country meant that the Republic was doomed… even without the genius, and the fire of Julius Caesar”.

Indeed, the problem of the army continued from the Roman Republic and into the next Roman age.

Politically rewired under Augustus, the Roman Empire would last for centuries to come, but the internal disputes at its inception had made the army an integral part of its political makeup.

It would not be able to free itself from this, the army being a tool of the emperor before eventually making him its prisoner. 

While the army had been Rome’s greatest weapon in the ancient world’s struggle for supremacy, the failure to politically control it may have been the ultimate cause of its eventual demise.

For more on Caesar and Rome, read 'Julius Caesar' by Nic Fields, 'Caesar's Civil War 49 - 44 BC' by Adrian Goldsworthy, 'Pharsalus 48 BC' by Si Sheppard and 'Roman Legionary 58 BC - 69 AD' by Ross Cowan. For more military history, visit Osprey Publishing

Also visit Karwansaray Publishers for more great titles, and read their volume ‘Ancient Warfare’ for a rich pictorial approach to military history.

'The Murder of Caesar' by Karl Theodor von Piloty