[Birds chirping] ♪ Narrator: It's the spring of 58 BC.

[Elk bellows] The people of Gaul face a new and grave threat.

♪ [Baby crying] ♪ [Horse neighs] ♪ Julius Caesar has completed his year as Consul of Rome and set his sights on conquest.

In this foreign land, there are few rules to constrain him.

[Baby crying] His army is carving its way through the country, subduing or slaughtering its people.

No one will stand in Caesar's way.

[Horse neighs] Man, voice-over: Times are changing in the Roman world.

Generals with their own armies are able to win unprecedented popularity, wealth, power, and these warlords are able to put the entire republic in their shadow.

♪ Caesar understands this.

He knows that only sweeping conquest can make him the greatest man in Rome... ♪ and he will stop at nothing.

[Horse snorts] [Sword unsheathed] [Stab] [Crying stops] ♪ It's brutal.

It's punishing.

It's genocidal in scale, but the reward of glory would burnish Caesar's name forever and put absolute rocket fuel into Caesar's political career.

♪ ♪ Narrator: At the heart of the most powerful empire in the ancient world stands Rome.

For 500 years, it was ruled by elected government, but in a little over a decade, this republic was overthrown by the ambitions of one man.

Man, voice-over: The story of Caesar is an incredibly enduring one, the resonance of it so powerful, it remains the most thrilling, the most extraordinary political story in Western history.

Narrator: Now, historians and experts who understand the nature of political power will chart his rise... Woman, voice-over: Rome is ungovernable, and there's only one man in the city with the power to take control of the situation.

Narrator: and ask how an individual can bend a centuries-old political system to breaking point.

Julius Caesar is the most dangerous kind of demagogue.

Narrator: This is the story of how ambition turns to tyranny... Man, voice-over: He's a disgrace in every single way.

He's immoral, he's irreligious, and he's a potential tyrant.

Narrator: and how a dictator is born.

Man, voice-over: The awful lesson is that in the end, the populist can corrupt an entire state.

Different man, voice-over: For every other political system that values stability and justice and liberty, that should be, at the very least, a wake-up call.

♪ Woman, voice-over: Democracy has to be constantly fought for.

♪ If we take it for granted, a new Caesar will come.

♪ [Birds chirping] [Water sloshing] ♪ Narrator: For two years, Julius Caesar has waged war on the people of Gaul, capturing territory, slaves, and bounty.

[Horse neighs] With his newfound wealth, he has enlarged his army and made rich men of his supporters back in Rome.

Man, voice-over: Caesar, throughout his political career, has always been an opportunist, but I think that "opportunist" is inadequate to convey the scale of what Caesar is aiming at.

The idea of conquering the whole expanse of Gaul, essentially what is now France, is stupefyingly ambitious.

♪ Narrator: Gaul is a vast region, stretching from northern Italy to the English Channel.

Caesar is governor of a narrow strip of Roman territory in the south.

From here, he's begun his quest to conquer more land for Rome and to subdue the Gaulish tribes.

Holland: For the Romans, the Gaul is the essence of the barbarian.

It's the figure of their worst nightmare.

Caesar himself says of the people that they are the least effeminate, the most masculine, the most dangerous, and yet he's perfectly happy to take them on.

♪ Narrator: Caesar believes he is the man to bring all of Gaul under Roman control.

Beyond the wealth he's winning for Rome, he's seeking not just fortune, but fame.

♪ Holland, voice-over: Caesar cannot possibly win the kind of status that he wants without a great feat of conquest, I think.

[Crows cawing] War is the great testing ground for Rome's leading men.

Caesar is pursuing the blaze of glory, so the defeat particularly of barbarians and of Gauls, I mean, this is something that will make his name echo down the centuries.

♪ Narrator: Caesar ensures news of his conquest reaches the people of Rome.

They delight in his success... ♪ Caesar is taking Rome to another frontier in his campaigns.

He does things as a general that people consider to be the realm of the gods by crossing huge rivers and huge landscapes.

Narrator: But the senate, the body of men who govern Rome, is divided.

Caesar's opponents see his growing power as a threat, but he still has allies.

His main backers are Rome's richest man Crassus and its greatest general Pompey, now married to Caesar's daughter Julia.

Caesar had persuaded Pompey and Crassus into a powerful alliance-- the Triumvirate.

They secured Caesar the top job in Rome--the consulship and the opportunity to conquer Gaul, leaving Crassus and Pompey to take care of their shared interests in the senate... ♪ but now, fueled by jealousy and resentment, tensions are rising between Pompey and Crassus, and they are losing their grip on Rome.

Woman, voice-over: Crassus still hates Pompey.

The Triumvirate looks like it's kind of wobbly.

It's not sustainable the way it's going.

The risk for Caesar is that if the Triumvirate proves to be utterly broken, then his capacity to hold his position in Rome is broken as well, and that means that his enemies can start moving in for the kill.

Narrator: Caesar's main opponents in the senate, the Optimates, see him as a threat to the republic, and are desperate to find a way to cut him down.

♪ Now, they plan to prosecute him for his shocking and violent behavior during his year-long tenure as consul.

Caesar's consulship sent ripples of shock through Rome.

He treated his fellow consul with a measure of violence.

Caesar's enemies said absolutely explicitly, "We believe that you should be prosecuted.

You have behaved illegally."

Holland, voice-over: His opponents see him as a criminal, and they are determined in the long run to prosecute him, to convict him, to destroy him utterly, and this becomes stronger and stronger the more glory that Caesar wins for himself in Gaul.

♪ Narrator: Leading the conservative charge to bring a prosecution against Caesar is his long-standing enemy Cato.

♪ Man, voice-over: In the minds of people like Cato, Caesar represents two very dangerous things.

He represents populism.

He's somebody who unashamedly tries to present himself as the people against the elite, and he represents the danger of tyranny.

He's somebody trying to promote themselves at the expense of the constitution, which stands for balance of power and no one person taking too much power.

Cato is going to try to do everything he can within the Roman law to defeat Caesar.

[Bird cawing] Holland, voice-over: Caesar's ultimate nightmare, the one thing that could drag him down, even after all he's achieved, is prosecution because if you can prosecute someone and convict them, then that person will have no choice but to go into exile.

You suffer a kind of political death, and that, for Caesar, would be a fate worse than death.

♪ Narrator: As long as Caesar is in Gaul, his position as governor grants him immunity from prosecution, but the senate still has the power to recall him.

♪ [All shouting] Narrator: In Rome, the Optimates ask the senate to vote on removing Caesar's governorship, but with many senators sharing in the riches Caesar's sending back to Rome, they fail to win the majority they need.

[Rustling] Caesar's command is safe, but it's a warning.

♪ He calls Pompey and Crassus to an urgent meeting in the northern Italian town of Luca.

[Squawk] [Squawk] ♪ Holland, voice-over: For Caesar, it's absolutely essential that the Triumvirate holds together.

The strains on the relationship between Pompey and Crassus is a real threat to Caesar.

He can't come to Rome and knock their heads together, so the conference at Luca is crucially important in keeping the Triumviral show on the road.

♪ Narrator: Caesar's plan is to persuade Pompey and Crassus to reunite by promising them each something they desire.

Haley, voice-over: Pompey at this point is in a peculiar situation because of his rapid rise to power on the back of military successes.

He is much loved by the people, but deeply mistrusted by the Roman senate.

He's always been on the outside looking in.

Narrator: While Pompey craves the kind of influence in the senate enjoyed by Crassus, Crassus is jealous of Pompey and Caesar's military success.

Man, voice-over: Crassus has a influential presence in the senate, but he lacks at this point the sort of major military undertaking that will provide status that he feels entitled to.

Caesar is conquering Gaul, and there is, no doubt, a sense of burning competition in Crassus' mind.

Narrator: In Rome, the annual election of the two consuls who lead the senate is imminent.

Caesar's plan is simple-- use the collective might of the Triumvirate to once again sway the voting public, but this time, Pompey and Crassus would become co-consuls, giving them the power to deliver what each of them wants.

Haley, voice-over: Pompey feels that if he can be consul, the leading politician and statesman in the city of Rome, he will gain the respect of the senate.

Santangelo, voice-over: And Crassus realizes that the consulship and provincial command afterwards for a major military undertaking will bring him the sort of outstanding status that he feels entitled to.

♪ Holland, voice-over: What does Caesar want in return?

He wants an extension of his command, and he wants that firstly so that he can complete his conquest of Gaul, but also because the longer he has his command, the longer he is immune to prosecution back in Rome.

♪ Haley, voice-over: The meeting at Luca is unprecedented.

Three men meeting secretly, deciding the future of the Roman republic goes against the idea of a republican form of government.

♪ Holland, voice-over: It's hard to think of any parallel in our democracy to what happens at Luca, its convergence of rival Mafia bosses.

It's the Joker, the Riddler, the Penguin coming together to carve up Gotham City.

♪ Narrator: The Triumvirate agree to renew their alliance and combine their powers.

[Squawk] [Singer vocalizing] Narrator: But for their plan to work, Pompey and Crassus must win the consulship election.

Santangelo, voice-over: Roman consuls typically don't run as a ticket, but when those two men start campaigning, it becomes very clear that there is a joint political operation unfolding.

Holland, voice-over: The news that the Triumvirate is once again putting Rome in its shadow is greeted by its opponents with simultaneous shock and horror.

[All shouting] Stewart, voice-over: There is one man who will obviously stand against them--Cato.

He's not senior enough or old enough himself to stand to be consul.

Instead, he gets his brother-in-law to run.

♪ Narrator: When word reaches the Triumvirate that the Optimates will stand against them, Caesar deploys a political tactic he's used with some success before-- violence.

Holland, voice-over: Caesar ensures that men from his legions who are serving in Gaul are able to go back to Rome to register their votes to boost the backing for his Triumviral partners.

Caesar's men, battle-hardened, unleash great bouts of thuggery and intimidation onto the streets of Rome.

Santangelo, voice-over: Pompey and Crassus are prepared to resort to intimidation, to violence in the run-up to the election, including, indeed, on election day.

♪ Narrator: It's the morning of the consulship vote.

Rome waits to discover whether the Optimates or the Triumvirate will take charge.

♪ Cato heads out to cast his vote.

Predictably, by this stage, because things are getting completely out of control, hired ruffians of Crassus and Pompey start beating Cato up... ♪ and in the most incredible plethora of violence, Cato effectively martyrs himself.

He allows himself to be beaten up because he wants people to see, in every scar on his body, the injustice and the horror that's happening in Rome.

♪ Narrator: The Triumvirate's strategy proves effective.

♪ Pompey and Crassus stand unopposed and win by a landslide.

♪ Haley: One of the perks of being consul in Rome is that you have special chairs at the front of the senate.

♪ When they take those seats, it sends a very clear message that the republic is being controlled by the Triumvirate.

♪ Holland, voice-over: Once Pompey and Crassus have become consuls, you know, they play their bit.

They secure Caesar another 5 years in Gaul.

Caesar can know that everything that he has achieved in bringing the Triumvirate back together again, that it is absolutely paying off for him.

♪ Narrator: Over the next year, Pompey, Crassus, and Caesar carve up the Roman world.

Each takes control of a foreign province with the military might, wealth, and prestige that brings.

Caesar keeps Gaul.

Crassus departs for Syria with plans to invade Rome's greatest rival-- the Parthian Empire, now modern Iran.

Pompey takes Spain, but will govern it from Rome, allowing him command of an army whilst remaining at the heart of the senate.

Santangelo, voice-over: It's become clear that the partnership-- the "3-headed monster," as a writer at the time calls it-- is achieving a degree of influence and power that is unprecedented and that is against the spirit, the, shall we say, deep-seated political culture of the republic.

There's no question about that.

Narrator: With the senate under the Triumvirate's control, Caesar accelerates his conquest of Gaul.

His opponents lie in wait for any opportunity to take him down.

♪ They get their chance when Caesar breaks a peace treaty and is said to slaughter over 400,000 men, women, and children.

[Wind blowing] It's a sacrilegious contravention of Roman law.

Cato leads a heated attack against Caesar in the senate.

[All shouting] ♪ Stewart: Cato tries to point out that Caesar is literally committing war crimes, so Caesar is just a disgrace, and Cato tries to demand the punishment for that war crime, which is that Caesar should be handed over to the enemy, but his demand is simply brushed aside.

Caesar is becoming so successful that nobody now wants to stand with Cato against Caesar.

♪ Holland, voice-over: Caesar really doesn't need to worry.

He knows that everything about his conquests is boosting his status, is boosting his prestige.

♪ Stewart, voice-over: Cato's now in a horrifying position.

Caesar, this man he despises, is now becoming so successful and popular that he's almost untouchable, whatever he does.

♪ Narrator: By the end of 55 BC, Caesar is riding high.

The Roman people love him, he's relishing glory in Gaul, and his allies control the senate.

Now, news arrives that further secures his bond with Pompey.

It's been 3 years since Pompey married Caesar's only daughter Julia, and now she's pregnant with their first child.

♪ Pandey, voice-over: Julia's baby represents the possibility of a lasting alliance between Pompey and Caesar.

Marriages in Rome come and go.

The divorce rate is actually pretty high, but having a child, that's something that will bind two families together in perpetuity.

As Julia's due date approaches, the entire Roman world is looking on... [Julia wails] Pandey: voice-over: but when Julia starts her labor, she suffers a great deal, and she is in a great deal of physical pain.

[Wails] ♪ Narrator: Julia dies in childbirth... ♪ and her baby dies a few days later.

♪ Haley, voice-over: Pompey, I mean, he was besotted with Julia, and so losing her must have been unbearable.

♪ Narrator: In Gaul, Caesar is awaiting news of his grandchild's birth.

♪ Instead, he receives notice of his daughter and her baby's death.

♪ Holland, voice-over: She was his only child, and when Julia dies, it's doubly a catastrophe for Caesar, both on the personal level, but also the political.

♪ Haley, voice-over: It's conventional to say that Roman women had no political power.

♪ I think that loses the point.

Women like Julia had a lot of political power.

She was the link between Caesar and Pompey.

With her gone, she's not there to mediate any differences between them.

♪ Holland, voice-over: A crucial bond between the two greatest men in Rome has been severed... ♪ and Caesar knows that the foundations of his power are a good deal more unstable than they had been previously.

♪ Narrator: A few short months later, Caesar receives a second devastating blow.

♪ The invasion of Parthia by Crassus has ended in disaster.

♪ He took a huge risk, and he paid the ultimate price.

♪ He is beheaded, and there are stories about melted gold being poured down his throat by the Parthians in mockery of his legendary wealth, but also in what could be seen as a denunciation of Roman greed.

♪ Hadrill, voice-over: It's a catastrophic defeat for Rome.

He loses legions.

It's a massacre of Romans, it's a dreadful humiliation, and that, of course, affects the way that we see Crassus.

He really is a loser.

Holland, voice-over: The death of Crassus is an absolute disaster for Caesar.

The Triumvirate depends on it being an alliance of 3 men, not two.

An alliance of two men, much, much easier for it to fall apart.

♪ Santangelo, voice-over: His death reshapes, quite literally overnight, the political scene in Rome because now, well, you no longer have 3 great men.

We have these two extraordinary individuals, Pompey and Caesar, with no one else in between, no mediator, no buffer.

It's them.

Are they going to coexist, or are they going to fight it out?

♪ Holland, voice-over: For Caesar, the absolute priority is to reaffirm his relationship with Pompey to maintain his ability to continue as governor in Gaul, so Caesar does what Romans, aristocrats conventionally do when they want to forge an alliance--he looks around for another female member of his family to marry off to Pompey.

So he offers his great-niece... ♪ and so Pompey says, "That's OK.

Thanks for offering, but no, no, thanks."

♪ Haley: And now Pompey finds himself in the position where he can choose which way he goes.

He can move closer to the Optimates in the senate, and at the same time, he knows that Caesar needs him.

This is what Pompey's always wanted.

All the balls are in his court now.

♪ Holland, voice-over: Caesar can no longer absolutely rely on their alliance holding together.

If there are other people who can offer more than Caesar can, then Pompey is absolutely in the market for accepting that.

♪ [Thunder] Narrator: Crassus is gone.

[Squawk] Narrator: Caesar and Pompey's alliance hangs by a thread... [Birds squawking] and Caesar is no longer pulling the strings in Rome.

The senate turns inward as men vie to reposition themselves.

Rome descends into chaos.

[Crow cawing] Violent gangs rule the streets, and one man is making the most of it-- an errant senator called Clodius.

He's a skunk.

There's nothing good about Clodius.

♪ He's a manipulator, a sociopath, a psychopath.

Any "path" you can think of, Clodius is it.

Narrator: Clodius holds a powerful position in the senate, one of 10 tribunes of the people.

Tribunes serve as a check on the senate's authority to protect the interests of ordinary Romans.

With special powers, tribunes can veto proposals or bypass the senate and take bills directly to the people.

By pushing through a law entitling every citizen to free grain, Clodius has won huge popular support.

Hadrill, voice-over: Clodius, essentially, creates himself a private army.

Holland, voice-over: There are people who are grateful to Clodius because he is providing them with bread, and they are ready to be recruited to his paramilitary gangs.

Narrator: Clodius uses his gangs to beat up anyone who stands in his way, a trick he learned from Caesar himself.

Holland, voice-over: Clodius, for years, had served as Caesar's agent, enforcing Caesar's interests in Rome, and Clodius learnt from Caesar that power can come directly from the people.

Clodius elevates this to a whole new level.

[Woman vocalizing] Political order in the streets of the capital rapidly starts to collapse.

Hadrill, voice-over: The behavior of Clodius makes Rome virtually impossible to function properly.

It's become a dysfunctional city, and he turns into a figure of terror for the Roman establishment.

♪ Narrator: Desperate to regain control of Rome, some conservative senators hire gladiators and thugs to fight back against Clodius.

♪ Then, on a road outside Rome... Clodius is discovered in a ditch.

♪ His body is carried back into the city and taken to his wife Fulvia.

Woman, voice-over: When the body comes, Fulvia receives it, and she does not do what should properly be done.

♪ For a proper Roman aristocratic funeral, she should wash the body and dress it before displaying it publicly, but she allows the crowd that has gathered to see his broken and wounded body, his bloody clothes, and she weeps in front of them.

♪ Several of Clodius' allies address the crowd, and so Fulvia's weeping and these speeches drive the crowd into a rage.

Rome is a powder keg.

It won't even take a spark.

It's going to be spontaneous...combustion.

Narrator: A rumor spreads that Clodius has been murdered by a prominent senator.

Fulvia leads an angry mob into the heart of Rome, where they stage an impromptu funeral right outside the senate house.

[People shouting] Schultz, voice-over: The unruly, angry mob break into the senate house, and in a rampage, they heap up benches and anything else they could get their hands on that would burn, and they heap it all up, and they put Clodius on the top of the heap.

♪ The choice to build Clodius' pyre out of items from the senate house is an indication of anger directed at the senate.

♪ Clodius' murderer is sort of the front man for the conservative faction within the senate, and so populist anger will have been directed at the elite.

♪ The pyre burns, and it burns so well that it also burns down the senate house, which is truly symbolic of the state of the republic in that moment.

The city is ungovernable.

It is uncontrollable.

♪ Hadrill, voice-over: The spectacle of the senate house burning, it's absolutely horrifying.

It marks the system, the republic, not in any sense working any longer.

Stewart; voice-over: For Cato, this is a moment of mounting horror, a sense of all the standards collapsing, and now we have the senate house literally burnt to the ground, mobs rampaging through the streets.

I mean, everything that he treasures about Rome and the republic is now in ruins or in flames.

♪ Narrator: With violence consuming the city, senators need to act fast.

A military general could help them quell the unrest... ♪ but even Cato knows that the only candidates with enough popular support are Caesar or Pompey.

Stewart, voice-over: The thing that worries Cato most at this moment is that Caesar is going to be able to come back.

He sees Julius Caesar as the embodiment of the threat, as an immoral man, and a potential tyrant, and so Cato decides in increasing desperation to do something that he'd refused to do years earlier, which is to try to ally with Pompey, and Cato has to gamble that Pompey is the lesser of the two evils.

♪ Narrator: In times of crisis, the senate have special powers at their disposal.

They could make Pompey what they call a dictator, an emergency office that gives one man sole control of Rome for a strictly limited period, but the Optimates hate the idea.

It goes against everything the republic stands for, so Pompey has offered a compromise.

♪ Hadrill, voice-over: What they come up with is a sole consulship for Pompey, extraordinary means and extraordinary measures.

Haley, voice-over: Pompey's position as sole consul is a watershed moment.

This has never happened before.

Pompey is overjoyed.

"The senate loves me."

♪ Narrator: After months of turmoil in Rome, Pompey's soldiers bring calm to the city streets.

♪ Then Pompey relinquishes his power at the end of his term, much to the approval of the Optimates.

♪ [Bird squawking] Narrator: In Gaul, Caesar is nearing the end of his term as governor.

For years, this position has protected him against his enemies in Rome.

Holland: As his 10-year period of office starts to come towards its close, the big question is what will his enemies do once he is a private citizen, in other words, once he is liable for prosecution?

Narrator: But Caesar has a plan.

Although he has opponents in the senate, he knows his success in Gaul has won him the love of the Roman people.

With the annual consulship election coming round again, Caesar plans to stand, certain he will win the popular vote.

Holland: This, of course, is crucial for Caesar's ambitions not just because it offers him the chance of a second consulship, but also because he will go straight from his governorship in Gaul to becoming consul.

♪ Stewart, voice-over: Cato is now very concerned that Caesar, flushed with his victories in Gaul, will be able to get himself elected as consul, and, by becoming consul, become immune to prosecution, so Cato will not be able to get him for all his lawbreaking.

♪ Narrator: For Caesar's enemies, there's a window of opportunity.

The senate still have the power to terminate Caesar's governorship.

If they can be persuaded to recall him, he could be forced to face trial before he has a chance to win the consulship.

The idea divides the senate.

♪ Holland, voice-over: The senate starts to split into two violently opposed factions-- the faction that supports Caesar and those on the other side who are absolutely determined to bring him down.

Narrator: Caught in the middle is Pompey.

He is forced to choose between his newfound favor with the Optimates and his old alliance with Caesar.

Trying desperately to reconcile these two irreconcilable blocs is Pompey, who wants to be the friend of both blocs of men.

Haley, voice-over: Pompey decides that the approval of the senate is more important than his relationship with Caesar.

♪ Narrator: Pompey stands with the Optimates and backs the debate about terminating Caesar's governorship in Gaul.

♪ Holland, voice-over: For Caesar, the fact that Pompey decides to move against him is a disastrous development because Cato's faction now absolutely has the wind in their sails.

♪ This, of course, stirs up Caesar's deepest worry... ♪ that all his astonishing conquests will be as nothing.

He is staring down the barrel of political oblivion.

♪ [All shouting] Narrator: On the 1st of March, 50 BC, the debate over Caesar's governorship begins.

It will end with a vote.

The Optimates need a majority to recall Caesar to Rome... but Caesar is prepared.

He's banking on a man he's bribed, another tribune of the people.

Caesar's man uses his power as a tribune to obstruct the debate.

[Men shouting] Holland, voice-over: The tribune vetoes and vetoes and vetoes every proposal that is put by the senate to try and strip Caesar of his command.

Narrator: The tribune not only blocks the proposal to revoke Caesar's governorship, he has a counterdemand, direct from Caesar.

Holland, voice-over: He puts a proposal to the Senate that if Caesar is stripped of his command, then Pompey should be stripped of his command in Spain... ♪ and this, of course, ups the stakes because it now means that Pompey's command as well is in play.

Pompey isn't going to give up his army.

Are you kidding?

His power lies in having an army at his command.

He is not going to give that up.

[All shouting] ♪ Narrator: Rome's two most powerful generals are now in a dangerous game of brinkmanship.

If they cannot resolve their standoff peacefully, everyone fears where it might lead.

Malik, voice-over: The tension between Caesar and Pompey at this point is escalating because of the back and forth they're having via the senate.

The problem is, the Romans know very well the logical outcome of this could be civil war.

Narrator: In a frantic bid to de-escalate, the senate again debates the proposal that both Caesar and Pompey give up their armies and that Caesar be allowed to stand for the consulship.

For the Optimates, this would mean abandoning their bid to prosecute him... ♪ but even Caesar's opponents are eager to avert catastrophe.

Haley, voice-over: The vote was 374 to 22 against, and it's clearly because the senate wants to avoid civil war.

And it might appear at that point that peace is around the corner, but, of course, Caesar's enemies aren't going to let that happen.

Narrator: Despite the overwhelming vote, one of the current consuls is a diehard Optimate.

Loathe to compromise with Caesar, he uses his power as consul to do something reckless and radical.

Hadrill, voice-over: It's absolutely outrageous for a consul to ignore the expressed will of the senate, but the consuls are very powerful people.

They have imperium, the right to control military strength, and in their determination to block Caesar, the consul actually takes a sword to Pompey and say, "Here, the command is yours, and you must protect us from Caesar."

Haley, voice-over: This is a signal that he has been appointed as commander of armed forces on behalf of the senate.

Hadrill, voice-over: Pompey should refuse.

If he had his head screwed on, Pompey should refuse... ♪ but the diabolical thing that the senators do is to persuade Pompey that he's their hero and that Caesar is the enemy.

He accepts the sword... and this is then a declaration that he is willing to take up arms against Caesar.

♪ Narrator: This raises the stakes once again.

♪ Pompey now has the authority to bring Rome's legions down on Caesar.

Holland, voice-over: Pompey has both symbolically and literally taken up the sword against him, and so Caesar now has absolutely no illusions as to what he's facing, but, you know, he makes one final gambit.

He sends a letter to the senate.

♪ Narrator: Caesar's letter is brought before the senate by one of his most loyal soldiers-- a man called Mark Antony.

Man, voice-over: Antony is one of those figures from antiquity that gets almost nothing but bad press.

Antony is a womanizer and he's a drunkard.

What's easy to overlook is that Antony's interested in literature, he's interested in art, he's one of the best-educated men of his time, which is why he's a terrific orator.

He joined Caesar's army as an officer, and they've become friendly, they've become close all during the context of the Gaulic War.

♪ Narrator: Caesar has used his popularity to get Antony elected as a tribune.

His role is to protect the interests of the Roman people, but Antony is really serving Caesar.

Hadrill, voice-over: When Mark Antony comes to the senate with a letter from Caesar, the senate won't even let him read the letter out, and they're simply putting their fingers in their ears and saying, "La la la la la la!

We don't want to hear you, Caesar."

Tatum, voice-over: But they're forced to hear it by Mark Antony, and the letter appears to be just another letter which says, "Let's disarm, let's find a way toward peace," but in addition to that sentiment, Antony will then go on to say, speaking for Caesar, that if this is impossible, if the senate insists on being so aggressive, then Caesar must defend his prestige.

He must protect the freedom of the Roman people.

They take it to mean that Caesar's threatening civil war.

♪ Holland, voice-over: I think, for Caesar, it's very clear.

Either his enemies in the senate back down or else, with reluctance, Caesar will have no choice but to defend Rome by marching on Rome.

[All shouting] Stewart, voice-over: Some people believe that it's possible to compromise with Caesar and avoid civil war, but Cato thinks Caesar is a fundamental threat to the republic and a stand must be taken, so he pushes very, very hard for an aggressive response towards Caesar.

In the heart of all politics-- it doesn't matter whether you're dealing with Putin and Ukraine or you're dealing with Hitler-- the question is, is compromise and peace possible with a tyrant, or is trying to compromise just a form of appeasement; it just encourages the other side?

Narrator: The senate must now decide-- compromise with Caesar or confront him?

For Caesar's enemies, backing down is not an option, so they bring a radical bill to the chamber.

Haley, voice-over: It's called the Ultimate Decree of the Senate, which would make Caesar an outlaw of the state.

This is as far from compromise as one can get.

We're talking about a decree that says, "You have permission to murder Caesar "if he crosses the boundary into Rome with or without an army."

This is huge.

It is absolutely huge.

Hadrill: And it's effectively a declaration of war on Caesar.

♪ Narrator: The senate are persuaded that this is the republic's last chance.

The emergency decree is passed.

♪ Tatum, voice-over: Antony is told in advance that if he interposes his veto against the senate's Ultimate Decree, if he exercises his rights as a tribune, he should be concerned for his personal safety... ♪ and so he flees Rome because of the menace of the senate.

♪ He makes quite a show of disguising himself as a slave so he won't be recognized, and he goes on to send Caesar an advanced notice that he is in peril.

♪ Holland, voice-over: The moment Caesar gets the news, he acts decisively.

He acts with his customary speed, but, of course, to act, he needs an army at his back, but he knows exactly how to press their buttons.

He says to them that the insult that is being done to his tribune Mark Antony, this is an insult to his men, too.

Tatum: The legions know the tribunes cannot be threatened.

They cannot be harmed.

Hadrill, voice-over: That's good propaganda for Caesar.

Turn against the tribunes of the Roman people, you're turning against the Roman people.

♪ Tatum, voice-over: If you side with Julius Caesar, you side with freedom.

[Woman vocalizing] ♪ Narrator: On the 9th of January, 49 BC, just north of the Rubicon, the river separating Gaul from Italy, Caesar hosts a dinner.

♪ Holland, voice-over: Caesar faces a choice.

He could lay down his commands, risk prosecution, and the very strong possibility of exile, or plunge Rome into a bloody civil war.

♪ He has been pushed into a corner by his enemies.

We are told that he hesitates in a kind of--an anguish of indecision... but in the end, he's a gambler, and as he has done throughout his career, he is ready to roll the dice.

♪ [Woman vocalizing] ♪ Holland: On the 10th of January, he gives the command.

His legion crosses the Rubicon, and the Roman republic collapses into civil war.

♪