Jan. 24, 2023

The Assassination of Emperor Caligula

The Assassination of Emperor Caligula

January 24, 41 CE. The notorious Roman emperor Caligula is assassinated at the hands of his own bodyguards.


Cold Open

It’s 40 CE on the coast of Gaul at what is now Boulogne, northern France.

A Roman legionary stands on the beach lined up in a battle formation with the rest of his legion. In front of them stands their leader, the notorious Roman Emperor: Caligula. As waves lap at the Emperor's feet, Caligula shouts at the sea with passion in his voice. The legionary is a veteran of Rome’s campaigns of foreign conquest. He has witnessed many battles, but never before seen anything like this.

With a flourish, Caligula waves his arms.

His trumpeters sound and then Caligula chants some words that are hard to make out. The legionary whispers to the soldier standing next to him asking what's happening. And the soldier chuckles ruefully, replying that Caligula has just declared war on Neptune, the god of the sea.

As the soldiers stand befuddled, Caligula bends down, fills his hands with seashells, and then rises. In a booming voice, he orders his men to follow suit and take what he calls the “spoils of the ocean” that are due to Rome. So the legionary and the rest do as they’re told. They bend down… and fill their helmets with seashells. Then they rise and stand at attention as Caligula strides through the ranks to examine their plunder.

The legionary dares to glance up as Caligula walks past. The emperor has a reputation for violence and cruelty. So when Caligula stops right next to the legionary, he quickly averts his eyes. But then, with a joyful bellow, Caligula announces that every man in the legion will receive 100 denarii in recognition of their great victory against the sea.

The legionary joins in the chorus of cheers that erupt from the ranks. But in truth, he has no idea what’s happening. Either Caligula is in a joking mood. Or the notorious Emperor is losing his mind.

It’s unclear what prompted Emperor Caligula’s odd behavior on the beaches of what is today Northern France. Perhaps his declaration of war against Neptune was meant to commemorate Rome’s dominance in its ongoing military conflict with the warriors of Gaul. Perhaps he was simply playing a joke on his troops. Or perhaps, the eccentric performance is a clear sign that Caligula is ascending into madness.

Regardless of the truth, there is no doubt that Caligula, a once popular ruler, is no stranger to unusual behavior. And in the end, his unhinged acts will lead to his downfall and prompt one of his bodyguards to plan and execute an assassination plot on this day, January 24th, 41 CE.


From Noiser and Airship, I’m Lindsay Graham and this is History Daily.

History is made every day. On this podcast—every day—we tell the true stories of the people and events that shaped our world.

Today is January 24th, 41 CE: The Assassination of Emperor Caligula.

Act One

It’s March 28th, 37 CE, four years before Emperor Caligula is killed.

24-year-old Caligula smooths down his robes as he slowly walks through the gates of Rome. Ahead of him is a carriage bearing the body of his deceased predecessor, Emperor Tiberius. But the mood on the streets of Rome is anything but solemn. The people of the city cheer as Caligula passes by. They call out praise and words of encouragement. Caligula tries to be reverent and respectful during the funeral procession, but he struggles to suppress a smile.

The death of Emperor Tiberius 12 days ago sparked celebrations in Rome. The people there had no great love for the reclusive Tiberius, who often escaped the bustle of Rome for quiet countryside retreats and ignored his imperial responsibilities. So within days of Tiberius’s death, the Senate marked a new beginning by ignoring the emperor’s succession plan. Instead of following Tiberius’s will and naming Caligula and his cousin Gemellus co-emperors, the Senate proclaimed Caligula as Tiberius’s sole successor. Now, as the Roman people cheer him through the streets, Caligula is relieved that they agree with the Senate’s decision.

After the funeral, Caligula is escorted to his new home, the imperial palace on Palatine Hill. He smiles nervously when a very powerful man is shown into his presence: Naevius Sutorius Macro.

Macro is the commander of the Praetorian Guard - an elite army unit that acts as the emperor’s personal bodyguard. But the Praetorian Guard can be fickle, and rumors are already circulating that Tiberius’s demise was hastened by Praetorian soldiers who smothered him. Caligula knows that if he is to remain emperor for long, he needs to cultivate Macro as an ally.

So Caligula offers Macro his hand and thanks him for supporting his proclamation as emperor. Macro assures Caligula that he was the best choice and says that Rome’s troops have been fond of Caligula since he joined his father’s military campaigns as a two-year-old wearing a miniature army uniform. Macro leaves Caligula with a word of advice though: hold on to the loyalty of the Praetorian Guard.

Caligula assures Macro that he respects the Praetorians. And as a gesture of goodwill, he intends to authorize generous cash payments to every member of the Guard. Caligula knows what he’s offering is little more than a bribe. But he’s relieved when Marco smiles and declares that the Praetorian Guard and Caligula will have a long and happy partnership. Caligula feels safe in the knowledge that he has the backing of one of Rome’s most powerful institutions. 

A few weeks later, Caligula is the guest of honor at a hearing of the Senate. He listens as different senators stand and praise his achievements.

Since becoming emperor, Caligula has issued many decrees and proclamations that overturned many of his predecessor’s unpopular actions. He recalled political opponents who Tiberius banished from Rome. He reformed the tax system and revived the practice of fair elections for public officials. He funded extravagant chariot races and gladiatorial games to entertain the people of Rome. And now, the senators wish to praise his reign with a public ceremony.

Caligula beams with pride as the senators vote on a motion declaring that the anniversary of his ascension will be a new public holiday. The motion passes easily. And then Caligula is delighted when he sees two slaves carry a glittering gold shield into the room. He smiles as a senator announces that the shield is being presented to him in recognition of his wise rule. And every year, on the anniversary of Caligula’s ascension, this golden shield will be carried in a grand procession through the streets of Rome.

As the senators continue to heap compliments on Caligula, he allows himself a moment of reflection. He is phenomenally popular with the people of Rome. The Senate and ruling classes are all happy with his rule, and he has no real rivals for power. He has the support of the army. And the Praetorian Guard have already pledged their loyalty. Caligula feels invincible.

But his successful reign will soon be interrupted by a mystery illness—and when it does, he will rise from his sickbed a very different kind of ruler: paranoid, vengeful, and violent. In the end, Caligula's popularity will plummet, and his opponents will see no alternative but to remove him by force.

Act Two

It's October 37 CE, seven months after Caligula triumphantly entered Rome as the new emperor.

Naevius Sutorius Macro, the commander of the Praetorian Guard, watches with concern as a physician examines Caligula, who lies in bed in his palace.

Over the past few months, Praetorian prefect Macro has become one of Caligula’s closest advisers and confidantes. So today, he is alarmed. Caligula’s face is pale. His mattress is soaked in sweat. But Macro sighs with relief when the physician remarks that the emperor is over the worst of his illness.

When the physician leaves Caligula’s bed chamber, the emperor closes his eyes to rest. Then, Macro steps forward from the corner of the room and quietly the emperor that he is pleased that he is recovering.

But Caligula’s eyes snap open at Macro’s innocuous words, and his face is seized with a sudden look of fury. The emperor declares that it was no regular illness that sent him to his sickbed. Caligula says that he has been poisoned and his recovery can only be a sign of divine intervention. The gods clearly do not want him dead yet.

Macro had no idea that Caligula suspected a plot against him. So he stutters as he asks who would want a beloved ruler like Caligula dead. His rage beginning to consume him, Caligula spits the name of his prime suspect: Gemellus, his cousin, the man who Tiberius wanted to be his co-emperor. Caligula then orders Macro to send soldiers to Gemellus’s house and force him to commit suicide as punishment. And if he refuses the emperor's order, the soldiers should do the job for him. Macro is shocked by the sudden, ruthless order. But he can see in Caligula’s face that the emperor’s mind is made up. Macro fears that if he refuses, the suddenly paranoid Caligula might suspect he is also conspiring against him. So reluctantly, he agrees to have Gemellus killed.

Macro also worries that Caligula’s determination to stamp out rivals will undo the good work that he has achieved since taking power. And he is right to be concerned. In the coming months and years, Caligula’s murderous repression escalates. And his popularity is further damaged by financial mismanagement.

Caligula has big plans for the future of his empire, and he’s not afraid to spend to achieve his goals. He funds the construction of new temples, aqueducts, and an amphitheater. He expands the imperial palace and has two large ships built for his own use. But as a result of his overspending, the treasury will run out. And faced with a financial crisis of his own making, Caligula is forced to resort to drastic measures.


Two years after Caligula’s illness, in 39 CE, an auctioneer stands on stage smiling at the crowd of rich Romans before him.

Then, with a dramatic flourish, he gestures to the item he’s trying to sell. It’s not a rare antique, but a man: a gladiator. Today, the auctioneer has been tasked by Emperor Caligula with selling off over a dozen imperial gladiators. But so far, the sale is not going well. The auctioneer does his best to encourage the room of potential buyers. He points out the veteran gladiator’s muscled physique. He explains that this is a man who has survived many bouts in the arena. But only one person makes a bid, and it’s far below asking price. Nervously, the auctioneer cuts his eyes to the back of the room, where Emperor Caligula reclines on a seat with a stony expression on his face.

Caligula is frustrated by the Empire’s financial situation. He’s tried all manner of schemes to raise money. He increased taxes and levied dubious fines against innocent Romans. But he didn’t raise enough to get the empire out of the hole caused by his own excessive spending. So he hopes to sell off over a dozen of valuable imperial gladiators. But the lone bidder isn’t offering enough money. It seems that everyone is living more frugally these days, even Rome’s richest citizens. Still, Caligula is desperate. And in one corner of the room, the emperor notices an elderly Senator has nodded off. Then, Caligula concocts a scheme to take advantage of the older statesman.

Caligula waves over to one of his servants and whispers into his ear. Then the servant makes his way to the front of the room where the hapless auctioneer stands on stage. The servant leans in close and gives the auctioneer his orders. The auctioneer looks up, locks eyes with Caligula, and nods. 

The auctioneer then points in the sleeping senator’s direction and announces a new bidder. Almost immediately, the original bidder ups his price. But the auctioneer makes a new bid on behalf of the sleeping senator. The price goes up again until the original bidder drops out, and the auctioneer announces that the gladiator has been sold to the sleeping senator, who is unaware of his purchase, and the good price he paid.

Over the next hour, the auctioneer sells every gladiator left on his list. And every time the price stalls, the auctioneer invents a bid from the still-slumbering senator. When he finally awakes, the auctioneer tells that he has purchased 13 gladiators and now owes the imperial treasury a small fortune. Caligula is confident the Senator will pay up. Because if he refuses, he will be met with the Emperor’s infamous wrath.

Caligula’s scheming ways add to an already growing sentiment in Rome that the emperor is out of control. Eventually, as a result of his financial mismanagement, his duplicity, and his violent despotism, members of the Praetorian Guard decide that Caligula must be stopped. In the end, the Emperor’s downfall will come at the hands of a man who is sworn to protect him.

Act Three

It’s January 24th, 41 CE, nearly four years after Caligula became emperor.

Cassius Chaerea, a tribune in the Praetorian Guard, stands at attention in an underground corridor in the imperial palace awaiting Caligula’s arrival. Cassius is one of the emperor’s bodyguards and sworn defenders. But today, he plans to break his oath.

Since joining the ranks of the Praetorian Guard, Cassius has become deeply concerned that Caligula’s unbalanced behavior is harming Rome. He also worries that Caligula is no friend to the Praetorian Guard. Caligula ordered the arrest and suicide of Naevius Sutorius Macro, the prefect of the Praetorian Guard who previously was one of the emperor's closest advisors. Cassius was not alone in thinking that Caligula needs to be dealt with. So when he first whispered his intention to assassinate the emperor to some of his Praetorian comrades, they urged him to do it. And now, the moment has come. 

When Cassius spots Caligula coming down the hall, he makes his move and advances on the emperor. But just before Cassius can perform the killing, a group of actors step in the hallway behind the Emperor. Noticing them, Caligula stops and spins around to talk with them. But Cassius realizes that this interruption has only made his task easier. When Caligula turns his back to the bodyguard, Cassius quietly draws his sword and approaches the emperor from behind. He then grasps Caligula’s hair and plunges his sword into the emperor’s neck.

The actors recoil in shock and horror as Caligula collapses to the floor. Cassius hears footsteps running toward him and turns around with his sword raised, ready to defend himself. But he lowers it when two other Praetorian Guards push past him and stab Caligula with their own weapons, shouting insults as they do so. Cassius is pleased that his bravery spurred other Praetorians into action. And by the time the deed is finally done, the emperor is dead, stabbed 30 times.

Praetorians will soon ransack the palace and kill Caligula’s wife and daughter. The only member of the imperial family who will survive that day is Caligula’s uncle, Claudius. And it is he who the Praetorian Guard will acclaim as the next emperor hoping that he will prove a more amenable and cooperative ruler.

Caligula was initially adored by many of his subjects. But over his brief, four-year reign, that adoration largely turned to fear and contempt. And as a result, he is perhaps most remembered for his financial mismanagement, and his proclivity for ruthless political violence; qualities that brought about his sudden demise at the hands of his own bodyguards on January 24th, 41 CE.


Next onHistory Daily. January 25th, 1964. A young entrepreneur founds Blue Ribbon Sports, a company that will one day be better known as Nike.

From Noiser and Airship, this is History Daily, hosted, edited, and executive produced by me, Lindsay Graham.

Audio editing by Mollie Baack.

Sound design by Mischa Stanton.

Music by Lindsay Graham.

This episode is written and researched by Scott Reeves.

Produced by Alexandra Currie-Buckner.

Executive Producers are Steven Walters for Airship, and Pascal Hughes for Noiser.