Original subtitles

It was mid-afternoon on 22nd January, 41 AD.

In the morning, the Emperor Caligula had been to the theatre,

but he had a bit of a hangover, so he decided to skip lunch

and freshen up with a quick bath.

That's where he was going, all on his own, down a back alleyway

in the palace compound, when he was jumped by a posse of soldiers.

The first blow to his neck, or some said to his chin, didn't kill him.

The next 30 or so did.

One nasty rumour said that the assassins ate his flesh.

Caligula was just 28 years old.

He'd been in power for less than four years.

It was an extraordinary moment in Roman history.

Rome's third emperor is Caligula, who has come

to stand for the corruption, horror and excess of Imperial Rome.

Psychopath and depraved, he is said to have ruled by the sword,

to have made his horse into a consul,

and to have insisted he be worshipped as a living god.

And ever since, he has become a template for tyranny,

with chilling echoes right up to our own age.

One of Caligula's favourite sayings was, "Let them hate me,

"so long as they fear me."

But how much of his story is true?

On the throne for just four short years, Caligula has left us

little physical evidence.

And to get behind the myths means a detective hunt

for clues all over the Roman world.

From the battlegrounds of his war hero father in Germany

to the island of Capri,

where people said he was schooled in the art of imperial power,

to the astonishing luxury of his life as emperor,

I'll uncover a Rome full of intrigue, murder and dynastic power

and come face to face with not just the monster, but the man.

So who was Caligula?

And why has he gone down in history as one of Rome's biggest villains?

The first clear sight we have of Caligula in any historical record

is a long way from Rome. From about the age of two,

Caligula spent his childhood on the road,

on the Empire's northern frontier,

parcelled round from army camp to army camp with his mum and his dad,

one of Rome's most charismatic military commanders.

By now, Rome had been under one-man rule for just 50 years.

And a generation after the first Emperor Augustus,

power was in the hands of one family - Caligula's.

His father was Germanicus,

the blue-eyed prince of the imperial family,

the nephew of the Emperor Tiberius, and himself tipped for the throne.

His mother was Agrippina,

the granddaughter of the first emperor Augustus,

who was himself the adopted son of Julius Caesar.

In the world of Ancient Rome,

you didn't get more blue-blooded than Caligula.

He was born Gaius Caesar Germanicus, a name he inherited

from his father, meaning something like Thrasher of the Germans.

And these were the family fields of honour, the killing fields

where Caligula's ancestors

cemented their reputations and political power.

Today, the Roman Museum in Xanten has been built

not far from one of the legionary camps

where Caligula spent time as a boy.

Inside, there is a remarkable collection of Roman military gear

from medals of honour,

with portraits of Caligula's dad Germanicus and mum Agrippina,

dished out to soldiers, to what was then

the most technologically advanced armour and weaponry on the planet.

There are cavalry helmets and daggers,

the remains of frighteningly powerful crossbows

and rainstorms of piercing arrows,

all of which remind us that Caligula's childhood playground

was not some cosy peacekeeping mission, but a vicious war zone.

But perhaps the museum's most intriguing artefact

is also its most humble.

This is a perfectly preserved Roman caligae, a standard army issue

soldier's sandal, made of tough leather with hobnails on the sole.

If there's one object that's really associated with Caligula,

it's the caligae.

The story goes that when he was a boy

and he was living on military camps with his parents,

his mum had him dressed up

in the uniform of an ordinary Roman soldier, right down to the caligae.

He was a kind of baby squaddie, the legionary mascot.

And we tend to think of the name Caligula as a rather grand

imperial name. In fact, it was the little boy's nickname.

It means little boots, bootykins or the kid in the caligae.

When he grew up, Caligula hated it.

It must have seemed as if he was being called Emperor Diddums,

or something.

And if you'd have asked him what his name was,

he would have said, quite correctly, his name was the Emperor Gaius.

The fact that even now, we still call him Bootykins,

shows just how successful his enemies were

in pouring scorn over him.

He himself would have been horrified to think of us calling him Caligula.

In the 1960s, in this small hilltop town in Umbria,

a group of workers dug up an enormous bronze statue

of Caligula's father, Germanicus,

that once stood on what was probably an army parade ground

on the edge of town.

It shows him in the classic pose of an imperial leader,

arm outstretched, addressing his troops.

And standing beneath him, one can't help but sense the status

and glamour of the man in whose shadow the little Caligula grew up.

One theory is that the statue was put up by Caligula himself

after becoming emperor,

in memory of the event that radically changed

the course of his life.

For in 19 AD, when Caligula was just seven,

Germanicus suddenly died on a mission to Syria, poisoned,

he claimed from his deathbed, by the Roman Governor Piso,

even perhaps under the orders of his own uncle, the Emperor Tiberius.

When the news of Germanicus's death reached Rome,

there was an absolute explosion of grief. Life stopped, it's said.

Ordinary people wept in the street.

They wrote up on the walls, "Give us back Germanicus."

The only people not grieving were the Emperor and his mother.

They weren't seen in public

and they didn't authorise a full state funeral

when the ashes of Germanicus came home to be put in the family tomb.

Eventually, Piso was put on trial,

but a few days in, he conveniently committed suicide and the trial

was turned into something more like a public inquiry.

And this is a copy of the record of that public inquiry,

the formal report inscribed in bronze, dated 10th December 20 AD.

Basically, the message is - the only person guilty here was Piso,

conveniently dead.

But the most extraordinary bit of the document,

and its real point, is down here,

where it says that one of these reports

is to be inscribed in the chief city of every province

and that it is to be inscribed in hibernis,

in the winter quarters, of each legion, cuiusque legionis.

This is mass communication, Roman style.

It's a major attempt to get the official message across everywhere.

It's hard not to think it all might not have been too little, too late.

The suspicions circling around Germanicus' death

would mark the start of an increasingly bitter feud

between Caligula's mother Agrippina and the Palace.

Convinced that Agrippina and her sons were plotting against him,

Tiberius banished her to a remote island off the coast of Italy.

And shortly afterwards, in 31 AD, he summoned the young Caligula,

aged 19 or so, to the island of Capri in the Bay of Naples.

This was the seat of Tiberius' power away from Rome.

It was from here that he ruled the empire by proxy,

from a whole suite of imperial villas built high into the cliffs.

Tucked away in a museum on the island

is one small trace of Caligula's stay here.

This may not look very much,

just like a bit of old Roman brick stuck in a wall,

but actually, it's the only physical evidence that we have

of Caligula's presence on Capri

because it's got his name stamped across it, Gaius Caesar.

And that raises the question of what he was doing here and why

Tiberius brought him, and there have been all kinds of theories.

Was he here to be under surveillance?

Was he here because Tiberius liked the kid?

Or was he here to be groomed to be Emperor

and learn to start building like an Emperor should?

Away from prying eyes, it was here, Roman writers later surmised,

that Tiberius schooled the young Caligula in the dark arts

of tyranny and excess.

The stories they told of what Tiberius got up to

here are all fantastical sex and violence.

Those people he wanted to get rid of, he had chucked over the cliffs.

And he'd stationed a platoon of sailors in boats at the bottom

to finish them off with their oars if they weren't yet dead.

And for poolside fun, he had a troupe of little boys -

his little fishes, he called them.

They'd been specially trained to swim between his thighs

while he was in the pool and nibble his genitals.

Whatever Tiberius really got up to,

we do know that Caligula's time in his charge was defined

by remarkable brutality, much of which was aimed at his own family.

For while Caligula was living in the lap of luxury,

his mother Agrippina was beaten up.

She lost her sight in one eye, she went on hunger strike,

was force-fed, until finally, she starved to death.

Not only that, both his brothers came to violent ends.

One by one, Caligula had lost his father and his mother

and his two elder brothers.

He and his sisters were the only ones in the family left.

It's a chilling reminder that in Rome,

the closer you were to power, the harder it was to survive.

In the vaults of the British Museum is one macabre memento from Capri

that sums up the young Caligula's life in the Emperor's court.

Looks like a real skull, but actually,

it's an extraordinarily lifelike work of art made of marble.

This must have made a stunning centrepiece

on the imperial dining table.

Rich Romans loved the idea of eat, drink and be merry,

because tomorrow you'll die.

But if you put it back in the context of the imperial court,

there are more sinister messages.

For a start, there's the violence of the Emperor himself.

Anyone sitting round this at the imperial dining table

must have been aware that their lives hung on a knife edge,

that they could be flavour of the month one minute, and dead the next.

The best advice was never to let your feelings show.

Keep poker-faced.

There's a horrible story of an imperial princess

who's dining one evening with her brother.

He keels over, dead, probably poisoned. What does she do?

What all good imperial princesses should do. She just goes on eating.

In fact, we're told that when Caligula was on Capri

and his relatives were being bumped off one by one,

he learned never to show any emotion at all.

Underlying all this nastiness was an issue that the Roman Empire

always struggled to work out,

the problem of succession.

Even though Roman power had now become a family business,

since the founder of the dynasty, Augustus, there was

no fixed system for passing the power on -

a fatal flaw that colours the whole Caligula story.

Succession posed a problem for the Romans for two reasons.

First, the Emperor isn't a real job.

It's supposed to be just a bundle of personal powers,

so you couldn't pass those on in a normal way.

But the other problem is that

Augustus and Livia didn't have children with each other

even though each had children with other people,

and what that means is, there isn't a clear line of succession.

A son to follow a father, a grandson to follow a son.

So when an Emperor begins to seem a bit sick or unreliable or gets old,

all sorts of groups begin to jockey for power.

There's the legions in the provinces.

There's the imperial bodyguards in Rome. You've got the courtiers.

You have the ex-slaves in the palace

who want to know who's going to own them next

and then you've got various imperial women

trying to get their sons into power.

So it's a very, very unstable situation.

Is it that instability and the uncertainty of it all

that both produces real violence

and also allegations and rumours of violence?

That's right.

The first thing that Tiberius does when he succeeds Augustus is,

he sends a boat to an island on which one of his relatives has been

kept in exile for decades to have the boy killed

because he could have been an alternative.

And what does Caligula do when he takes power?

One of the first things he does is, he has his cousin,

a little boy named Tiberius Gemellus,

murdered because he's somebody else who could have been Emperor.

What's amazing is that, for the first 100 years of the Empire,

there's not a single Emperor

about whose death there isn't some kind of allegation

that he was bumped off,

that the poisoned mushrooms had done him in.

There is that story of Caligula who, some people said,

had actually smothered Tiberius when he was asleep

in order to take power himself.

And the other story is,

he got the captain of the Praetorian Guard to do it for him

because Emperors have people to do the smothering for them.

However Tiberius really died, two days after his death

on March 18th, 37 AD,

the Senate declared Caligula Rome's third Emperor.

He could now triumphantly return to Rome

as the ruler of the known world.

He was just 24 years old.

At the time, he must have seemed the best choice.

As the childhood mascot of the troops

and the son of the great Germanicus, he had the support of the army.

And, as the great-grandson of Augustus,

he could claim a direct blood line back to the founder of the dynasty.

And to the adoration of the crowds,

one of Caligula's first acts as Emperor

was to make a huge play of these family connections.

Braving the stormy seas, he made a great song and dance of bringing

the ashes of his dead mother back to Rome, burying her with his own hands

here in the enormous family tomb, built by his great-grandfather,

the Mausoleum of Augustus.

BELL TOLLS

At the Capitoline Museums in Rome,

the whacking tombstone Caligula put up to his mother still survives

and it's so much more than just a grave marker.

It starts by saying OSSA.

These are the bones, in fact the ashes of Agrippina,

the daughter of Marcus Agrippa,

the grand-daughter, NEPTIS DIVIAVG

of Augustus, the first Emperor,

who's now a god, a Dyeus.

And she's the wife, the UXOR of Germanicus Caesar,

the golden boy of the Empire

and she's the mother, MATRIS,

of Gaius Caesar Augustus Germanicus,

PRINCIPIS, the Emperor Caligula.

In a way, it says just as much about Caligula.

This is his manifesto to his right to imperial rule.

But there was another way in which Caligula could get

the message across about who was now in charge,

by the money he minted, stamped with his portrait,

on which he showered down on the people of Rome.

Caligula is supposed to have been absolutely spectacularly generous.

He's said on some occasions to have gone up to the first floor

of a building in the Forum and actually thrown money,

thrown coins at the crowd.

They would have got some good cash to take home

but, more important in a way, you'd also go home with a message

because one of the ways that Emperors could

get their version of events

and their slogans across to the Roman people at large,

was to put them on the coins,

so you literally carried around the imperial propaganda in your pocket.

In Caligula's case, they hammer home the point about the royal blood

flowing through his veins.

This one shows Caligula on one side,

his father, the great Germanicus, on the other.

Another shows a carriage parading a statue of his mother

in celebrations founded in her honour.

And even more important, this one shows Caligula sacrificing

a bull at the temple of his great-grandfather, the god Augustus.

This one has an even more pointed message.

On the one side, there's a really gorgeous portrait of Caligula

and his name here, Gaius Caesar.

But on the other, you can see what must be him standing on a box,

his arm outstretched and he's talking to a group of soldiers

and it says at the top, ADLOCUT, short for adlocutio,

the speech of the Emperor, to his troops and underneath, C-O-H,

short for COHORTES, the cohorts of the Praetorian Guard.

And the message of this is clear.

Whatever family background you have,

whatever deals you've done,

nobody in Rome can become an Emperor

unless they've got the support of the army.

And this is what many modern despots and tyrants have also discovered.

Without the support of the troops,

you're either deposed or you're dead.

These coins give us an idea of how an Emperor

branded his image in the days before TV and radio.

Alongside stamping his face on the cash,

cheap cameos of Caligula were cut from glass and clay

and portrait busts were sent out across the Empire to be copied

and turned into a whole gallery of imperial statues.

If you've ever wondered

why there are so many heads and so few bodies, one reason is

that the heads were always meant to be replaceable.

You can see just how easy it would be to take one head out

and pop another one in.

Once established on the throne,

one of the ways Rome's new Emperors cemented their power was to build.

And even if Caligula ruled for just four years, we know that some of

Rome's most iconic ancient monuments started life under his watch.

There were the aqueducts, the Aqua Claudia and the Anio Novus,

bringing water from over 40 miles away to the centre of Rome.

The Obelisk that now stands in front of St Peter's is also Caligulan,

shipped over from Egypt on an enormous specially-built boat.

And then there was the most obvious statement of Caligula's power,

the imperial HQ on the Palatine Hill,

whose Latin name Palatium, gives us our own word, palace.

Most of what we now see here dates from long after Caligula's death.

His own building was destroyed in the great fire of Rome in 64 AD,

but it seems that Caligula was the first Emperor to remodel

the imperial residences to make them more palatial in our terms.

The Emperor didn't just live on the Palatine Hill.

Caligula also inherited vast pleasure gardens called Horti,

on the outskirts of the city.

One of them, the Horti Lamiani,

is still a garden of sorts in modern Rome and it's the location

of the only eye-witness account of Caligula in action that we have.

It was written by Philo, a Jew from Alexandria,

who had come to petition the Emperor

against political discrimination back home

and it's a rare glimpse of Caligula the Emperor,

face to face with his subjects.

When Philo and his delegation get to their appointment,

they discover that the Emperor's mind

is actually on home improvements

and they traipse around after him through the gardens

as he goes from pavilion to pavilion, planning his makeover.

When they get his attention, they bow down to the ground.

But it doesn't cut much ice with Caligula, who simply says,

"So you're the god-haters who don't think I'm a god, then?"

And he follows that up by asking,

"And, anyway, why don't you eat pork?"

One of the Jews thinks quickly on his feet and said,

"Well, quite a lot of people don't eat a lot of things.

"I mean, some people don't eat lamb."

"I'm not surprised," said Caligula, "It tastes horrible."

And the flunkies all laugh.

It's a wonderful and horrible vignette of the day-to-day

exercise of imperial power.

There's no cruelty here, there's no violence.

There's even a bit of banter.

But, all the same, it's humiliating.

Caligula's message is quite clear.

My fancy window glass is more important

than the Jews of Alexandria.

It's a revealing story and it also tells us

a lot more than we might think about imperial luxury.

For one of the ways Emperors dazzled you with their power,

rammed it in your face, was with the very trappings of their world.

And it's from the pleasure gardens that we can still find

traces of Caligulan splendour.

From them have come some of the most impressive

and famous statues of Ancient Rome,

such as the Discobulus,

the discus-thrower, a version of an earlier Greek masterpiece.

There's the Maid of Anzio

found at the palace where we think Caligula was born.

And the Sleeping Hermaphrodite,

a wonderfully urbane joke,

the kind the palace just loved.

On the one side, she's a luscious sleeping woman.

On the other, she's definitely more of a bloke.

And in the 1870s, excavators dug up an astonishing find

in one of the imperial pleasure gardens that used to be Caligula's.

Hundreds of precious stones, rubies, garnets, carnelians,

bits of rock crystal and amber

embedded in amazing frames of filigree silver and gold.

When this stuff was first discovered in the 1870s,

no-one could quite work out what it was.

One idea was that they'd come across a throne room,

but there's just so much of this stuff, I think we have to imagine

precious stones literally embedded in the palace walls,

twinkling in the lights at night, looking amazing,

or perhaps a bit tacky during the day.

We do know that Caligula was dead keen on pearls

and one contemporary witness says he actually used to like slippers

with pearls sewn into them,

which, if you ask me,

is a far cry from those little military boots he started out with.

It's a cute vision.

A newly-crowned Emperor showing off his pearled slippers

to his flunkies.

But it's also another example of how the imperial family

used the ostentation of their world to unsettle and disarm.

This is one of the most iconic

and impressive imperial paintings from Ancient Rome,

the so-called Garden Room,

designed for Caligula's great-grandmother Livia,

in whose home Caligula spent time as a boy.

It's an impossibly utopian scene.

The trees are all full of perfectly ripe fruit.

Every flower is perfectly in bloom

and in the gloom of the flickering lamps 2,000 years ago,

it would be hard to know whether we were looking at a real garden

or a painting of one.

Of course, that sort of illusionism is one of the most impressive

trademarks of Roman art.

But it's also slightly unsettling.

The blurring of the boundary between the fake and the real

is one of the factors about Roman court culture that made it so scary.

You never quite know

whether what you're looking at is real or an imitation.

Pretence or reality.

On the one hand, what you think is real turns out not to be

and there's a great story about going to dinner with Caligula,

looking at the fantastic spread, it all looks wonderful

until you spot that the food on the table is made of gold.

It's very precious but what are you supposed to do?

Can you pretend to eat it?

And on the other hand,

what you think is fake can turn out to be deadly real.

There's another story of Caligula having what looked like

a practice gladiatorial bout with an opponent, with wooden swords,

except Caligula had a real weapon.

So this all looks very impressive.

It's all very lovely, but it reminds us that there's a more shadowy,

sinister world of smoke and mirrors in the Imperial Court.

It's a perfect example of the choreography of threat

that lurked beneath everyday palace life.

A threat, if you think about it from the Emperor's point of view,

that worked both ways.

The labyrinthine corridors of the palace were teeming with people,

from visiting dignitaries and spies

to the collectors of the Imperial rubbish.

It must have been a security nightmare.

How did the Emperor ever know who was who?

And how did he marshal his own security?

They did have a system of passwords.

The Emperor would issue a new one each day

and you would have to say the word if you were challenged.

But that wasn't enough for the most anxious of emperors.

One of them is said

to have had the walls of the palace lined with mirrors

so he really could see who was coming up behind him.

In this world, where the Emperor was always watching his back,

the people he ended up trusting the most

weren't just his personal security force, but also his slaves.

And high up on the wall of the museum in Rome

is the record of the staff from one of Caligula's actual palaces.

Each one tells us what they did.

Here's one, for example, "Saturninus Svaia".

That is short for "Svairista".

It means ballplayer, but perhaps Saturninus was a personal trainer.

We've got Argaeus, he's a Gubernatio,

the helmsman, perhaps, on the Imperial yacht.

But perhaps my favourite of all is this chap here, Venustos Spec.

Spec could be short for "speculatos".

Venustos might have been a watchman or spy.

But it could also be short for "specularius",

in which case he was the guy who made the mirrors.

It's a wonderful snapshot of the underbelly of court life.

But it would be a mistake to think that they were just lowly servants.

Some of them played a vital role

in the palace's strategy of control and fear.

Aphetos, here, he's an "invitato".

He's the guy who controls the guest list at the palace dinner parties.

Now, Roman aristocrats

wouldn't have touched this kind of job with a barge pole.

But these guys could have quite a lot of power.

And Romans told quite a lot of sometimes wild stories

about just how powerful these imperial slaves and ex-slaves were.

Caligula is supposed to have had one called Protogenes,

who carried around with him under each arm,

with more than a bit of menace and ham-acting at the same time,

two different files,

one labelled "dagger", the other labelled "sword",

as if they contained the lists inside

of who was to be put to death and how.

It's not hard to see why the Emperor relied on these guys.

They didn't represent a direct threat to him,

they weren't going to become emperor themselves.

And, after all, he owned most of them.

But in the end it didn't do Caligula any good.

Some of them are supposed to have been involved

in the final plot to kill him.

This is now one of the most powerful images of Caligula that we have.

A man who was paranoid about his own security, and not unreasonably.

As he no doubt learned from the fate of his own family under Tiberius,

conspiracies were an absolutely inevitable part of Imperial Life.

If Caligula is always looking behind him, if he is always watchful,

are there people who really are out to get him?

Yes, there were people out to get him,

and I think they were of two quite different types.

Either they are people within the extended family who accept

that Rome is now a dynastic autocracy of which they are part,

but want themselves, rather than Caligula, to be the autocrat.

But there's also another type of potential opposition,

which is people who don't think

that Rome ought to be a dynastic autocracy at all,

and they want to put the clock back to the Republic

run by the Roman aristocracy, run by the Senate.

But it's really the first type, the family trying to replace him

from one of their own number, that looks like the most important.

We have most evidence for it. Yes.

His brother-in-law, Aemilius Lepidus,

was executed for plotting against him.

And his wife, Caligula's sister,

and also Caligula's other surviving sister,

were both exiled as a result.

So clearly, Caligula saw this as a threat from those closest

to him inside the family, to his own position.

So in a sense, he is quite right to be looking over his shoulder

because the people who've got the knife out are likely to be

the people he's hanging out with most days of the week. Yes.

And he doesn't know how many of them there are.

Ever since, historians have wanted to make this family plot

one of the turning point in Caligula's reign

that marked his transition from golden boy with promise

to the maniacal monster we've all come to know.

But the fact is that this is the period of Caligula's life,

his time in power, about which we actually know the least.

Were these conspiracies real conspiracies?

Was this the moment that he started to lose his grip?

We don't know.

What we do is that this is when the stories of madness

and excess that have come to define Caligula mostly start.

And perhaps the most famous is that he gave his favourite horse,

Incitatus, that's "Speedy", his own palace.

That he fed him oats mixed with gold

and that he made him a consul of Rome.

The fact is that no ancient writer ever says that Caligula

made his horse a consul.

What they say is that he planned to or that people said he planned to.

I'd be pretty certain that what underlies all this

is a bit of banter, a Caligulan joke.

I can imagine him at dinner one evening with his friends

among the aristocracy and he's trying to needle them a bit.

He's saying, "Oh, you're a right hopeless lot,

"I'd rather have my horse consul than one of you."

And that then goes down in history as if he was serious.

But anyway, we all do love stories about monarchs

and their pampered pets.

Just think of our fantasies about Queen Elizabeth

and her corgis, how they have diamond collars

and they eat out of silver bowls

and they're served by footmen in uniform.

I wonder what we'd say

if we found that she'd nicknamed one of them Prime Minister?

And it wasn't just stories of unbridled excess.

Much of what else was thought wrong with Caligula

came down to his sex life.

It was said he turned his palace into a brothel,

loved dressing up in women's clothes and was so insatiable for sex

that he wore out his male partners.

For us, Caligula has become more than anything

a byword for sexual excess and perversion.

We can hardly hear his name without conjuring up images

of drunken orgies, sex in the wrong place with the wrong people,

with little boys, married women, virgins and, most notoriously,

with his own three sisters.

If we were making a porn movie, Roman-style,

we'd be bound to cast Caligula in the lead.

And if these stories have been added to

and embellished over the years,

they actually first appear in sources

written years after his death,

mostly by the second century biographer Suetonious.

And they tell us just as much about the anxieties

of the Roman elite as they do about Caligula.

So you get these tales about, you go to dinner with Caligula,

you're a senator and you take your wife

and then in the middle between courses, you suddenly discover

that the Emperor has gone out of the room with your wife.

They come back a bit later, they all look a bit flushed

and then the Emperor says, "Oh, she's not very good in bed, is she?"

Yeah, and associated with those stories,

there's the account of how people are coming to the banquet,

Caligula is on his couch, people file past the end

and he acts like someone at a slave market,

sort of checking out the girls,

trying to decide which one he's going to select for later.

So this is how the Emperor shows his power,

by humiliating the elite in all sorts of different ways.

This is one way amongst many.

But perhaps the most damning story was Caligula's incest

with his favourite sister, Drusilla, with whom, as a boy,

he was said to have been discovered in bed by his own grandmother.

There's no actual accusation of incest by anybody contemporary,

absolutely contemporary with Caligula, is there?

And even this Suetonious stuff,

where he's talking about granny finding them in bed,

it's quite interesting that even Suetonius is only saying,

"People used to say that. The gossip was..."

Whereas he's quite clear that incest took place,

when it gets to the detail, it's all...

Kept at a distance.

Yes. I think even Seneca, who is pretty much Caligula's contemporary,

he does talk about when Caligula's sister Drusilla dies,

Caligula's excessive grief for Drusilla.

He doesn't know what to do with himself,

he dashes off to the country, he dashes back to Rome,

he tries to console himself with gambling.

He goes around in a terrible state.

But he doesn't link that to perverse sexuality.

I think there's also the dynastic aspect of it.

The stories about incest are partly about their anxieties

about the way that power is now transmitted in the Roman world.

Instead of it going from one lot of middle-aged men

to another lot of middle-aged men

through a proper process in the Senate,

it's one family that's holding on to power

and the women in the family then have influence in a way

they never had previously done under the Roman Republic.

So really what the stories are telling us,

they are telling us about power? I think that's right.

He's a youngish man, he's not a great military leader

or anything like that, but he's got all this power

as leader of the Roman world.

His relations with the Senate are clearly very uneasy.

So they tell these stories about his outrageous behaviour.

Perhaps this is a clue to one of the problems of Caligula.

Whereas Augustus and Tiberius had come to power after prominent

military careers, "Bootikins" was thrust on the throne at just 24.

Without the military pedigree or political experience

to earn the elite's respect,

it's hardly surprising that he might cast around

for alternative, more king-like models of leadership.

And that included presenting himself as both Emperor and God.

The boundary between Roman emperors

and the gods was always a fragile one.

But Caligula trampled right through it.

He is said to have insisted

on being worshipped as a god in his own lifetime.

And to make matters worse, we are

told he transformed the most symbolic space in Rome,

the People's Forum, into his own stage to be worshipped.

One story was that he turned the Temple of Castor and Pollux

into the porch of his own house

and used to go and sit there between the statues of the gods,

waiting to be worshipped.

Another story was, he used to go up to the Capitoline Hill

to talk to Jupiter there.

And then built a bridge between the Palatine

and the Capitoline to make those conversations a bit easier.

It's even said that he had flamingos sacrificed to him.

If there's now nothing left of these buildings above ground in the Forum,

archaeologist Henry Hurst has uncovered evidence beneath

that suggests they might not be entirely fantasy.

We dug over all of this area and we're very lucky

in that we found some unusually well-dated remains.

We could date them

pretty much to around 40 AD, around the time of Caligula's reign.

And what they consisted of was a large courtyard going that way

towards the hill and behind it a very grand room

and a grand courtyard. Then where we are, a big enclosure

with a central monument.

The combination of that and this grand courtyard and room

makes one think of some sort of a palatial complex.

And on the other side of that wall is the Temple of Castor and Pollux.

Yes, so the story that Caligula extended the palace out

towards the Forum and made the temple his vestibule

seems quite possible because these remains are huge and palatial

and very close to the back of the temple.

And what about Caligula's fantastical bridge to Jupiter

on the Capitoline Hill,

which, if true, would have spanned a distance of over 250 metres,

and been 30 metres above the ground?

The sane and traditional view of this is that the bridge

was just a timber footbridge, which went from somewhere high up,

using the roofs of buildings, and ended up over in the Capitoline

so you wouldn't find any traces archaeologically.

But we have the mystery of what we're standing on.

What it looks really like is a pier of the Roman bridge at Verona.

These look like that quite a bit, so we thought, is this a bridge pier?

And in favour of that is this question of levels

because the temple behind us there is one storey up from where we are.

There's also the story about how Caligula threw coins

from the roof of the Basilica Julia, also one storey up,

and that was just over there, so it would be quite sensible

if you were having a bridge for it to be effectively one storey high

so that it could link these things all at first floor level.

So a raised walkway and then up to the Capitoline.

And then eventually up to the Capitoline, yes.

It's just a small block of marble, a tantalising clue

to the lengths Caligula went for his own self-aggrandisement.

But it also points to the difficulty we now have

in separating fact from fiction.

After just four years in power,

there's little hard archaeology that we can tie to Caligula for certain.

But there is one site not far from Rome where we can.

This is Lake Nemi, one of Caligula's favourite places.

It's where all the myths come together.

The uncontrolled extravagance, the divinity, and even the violence.

It was known in the ancient world as the speculum Dianae -

the mirror of Diana.

And in the 1930s,

it was the site of one of the most stunning finds in Roman archaeology,

two enormous floating villas that were so large

and so lavish that they've become the ultimate symbols

of Caligula's excess towards the end of his reign.

And unsurprisingly, it was Italy's 20th-century tyrant, Mussolini,

who spent a fortune raising them from the mud and installing them

in a huge museum at the end of the lake.

The shells of the boats were tragically destroyed

in the Second World War.

Now we've only got models, but much of the hardware still survives.

No doubt whose boats these are!

It says Gaius Caesar Augustus Germanicus.

These are Caligula's barges.

It's a bit hard to know what a water pipe is doing on a boat.

They can't be ordinary boats.

Perhaps they're bringing water to Caligula's hot tub under the stars.

Suetonius has left us a vivid description

of other Caligulan boats,

so luxurious that they had jewelled prows, sails of purple silk,

and bathrooms of alabaster and bronze.

Long thought a myth,

the boats of Nemi hint that they might in fact be true.

For alongside the naval hardware of the ships are glimpses

of astonishing imperial luxury.

There are rows of columns made from Grecian marble,

sinister sculptures of Medusa heads,

and huge golden hands,

beautifully sculpted mooring rings of wolves and lions,

and balustrades cast in solid bronze.

There have been all kinds of theories about what these boats

were actually for.

Some people have thought they must have been religious.

Was it here that Caligula came to commune with the goddess Diana

by the light of the moon?

Was one of them a temple to the Egyptian goddess Isis?

Or were they just very lavish pleasure barges?

Romans with too much money loved nothing more

than to build out onto water. Was that what Caligula was up to?

The boats of Nemi will no doubt always remain an enigma...

..but there is one place on the lake where Caligula's intentions

come into sharper focus.

All around the shore were dozens of shrines and temples

that went back hundreds of years.

And one of them raises troubling questions

about whether he was a victim or actually a colluder in his own fate.

This was once the sanctuary of Diana,

a richly decorated temple in a grove of sacred trees.

There was just one weird thing about the sanctuary of Diana

and that was the priest in charge, the so-called King of Nemi,

the Rex Nemorensis.

First of all, he was a runaway slave, and secondly,

in order to get the job, he had to kill the present incumbent.

If you wanted to become Rex here, you came to the sanctuary,

you went and found the special sacred tree,

you pulled off a branch.

If you managed to pull off that branch, you were allowed

to challenge the current priest to a fight to the death.

If you won, you became Rex yourself,

but of course you also got a death sentence

because someone else would be along sooner or later to challenge you.

Ancient writers tell us about seeing the priest in this sanctuary.

He had a sword in his hand

and he was always looking furtively about him, for obvious reasons.

The ritual of Nemi harked back to a very primitive level

of ancient religion,

and Caligula was said to have revived it with glee,

finding a slave to come and kill the priest in charge.

Whether Caligula did that because he wanted to inject

a bit of religious reality into what had become a charade,

or whether it was just capricious sadism, we don't know,

but it's hard not to think of the King of Nemi

as an uncanny double of the Emperor of Rome.

Both were looking behind their backs,

and maybe Caligula had spotted that too.

However knowing Caligula might have been, in the end it didn't save him.

On 22nd January, 41 AD,

he was assassinated after just three years, 10 months,

and eight days in power.

And if the facts of Caligula's life might forever elude us,

ironically it's his death about which we know the most,

thanks to a graphic account written by a Jewish historian,

Flavius Josephus.

Peter Wiseman is taking me to where he thinks is the exact spot

where Caligula, the Emperor Gaius,

was set upon by members of his own personal security force.

He sees, coming towards him,

a colonel of the Praetorian Guard called Cassius Chaerea,

whom he knows of old. So, he feels safe. He thinks he's safe.

Cassius Chaerea, however,

is the leader of the assassination conspiracy,

and Chaerea draws his sword and he brings it down as hard as he can.

Gaius is staggering around, totally disoriented,

and the guy who actually gave him the final blow

was a man called Aquila, so he's the man who has the credit

for the assassination of the Emperor Gaius - Caligula.

Are people pleased - a tyrant is dead? Some people thought that.

What you have to understand about Gaius Caligula is that he was

enormously popular with the ordinary population.

He was a Caesar, who was the son of Germanicus,

he was the great-grandson of Augustus,

he was the great-great-grandson of Julius Caesar.

All of these were popular heroes. He was their popular hero,

and they hated the idea that people - senators, senior army officers -

should take it upon them to kill their man.

But there's a sort of irony to this, isn't it, because this is not an

uprising of popular will, this is a take-out move

by the Praetorian Guard.

Yes, a small group of senior officers

who were also involving senior senators.

It's a question what they expected to happen afterwards.

It seems that Chaerea

and the others were idealistic enough to believe that, in killing Gaius,

they would put an end to what we call the principate.

There wouldn't be an emperor any more.

But in the end they get this very, very brief little flowering

of what looks as if it might be about to become the overthrow

of autocracy entirely,

and the return to the republic, the little bit of debate,

and then half an hour later they found Caligula's uncle,

Claudius, to put back on the throne.

That's because the Praetorian Guard itself

depended on there being an emperor.

It was the ultimate betrayal, and a chilling reminder

that in Imperial Rome it was not the emperor, but the army,

who held the reins of power.

But there's one final chapter in Caligula's story which adds,

I think, to his terrible reputation.

There's evidence that attacks on his memory began

almost before his body went cold.

To justify his assassination,

the new regime condemned him as a tyrant.

His uncompleted building projects were then taken over

and inscribed with Claudius's name.

Some of his coins were defaced,

his initials symbolically scratched out,

and in many of his official statues,

the heads were either replaced or destroyed.

At the wonderful Montemartini Museum in Rome,

there's a strange bust of Caligula's uncle,

the new and in many ways just as vicious emperor,

which underscores the shifty awkwardness

of the transition of power.

The face looks for all the world like the Emperor Claudius.

It is a bit middle-aged and frowny, just how Claudius is often shown,

but he's got this strangely bouffant fringe.

And if you go up above him, you can

see the whole bouffant hairstyle has been roughly chiselled off.

What has gone on is that a statue of Caligula has been

changed into a statue of Claudius.

And it looks pretty weird, except if you imagine that this head

would have been on a full-length statue, and if you get low down,

well, actually, he works pretty OK as Claudius from this angle.

Now, it's a way of saying Caligula is obliterated

and Claudius is now on the throne.

I have a sneaking suspicion that it also says, actually,

the new emperor is only the old emperor with a re-cut face.

This hybrid head gives us a clue as to why it's always been

hard to come face-to-face with the real Caligula.

In the bloody transition of power, his real face has got lost.

And to find him, you now have to look for him in other ways.

In the shadow of his heroic father on the battlegrounds of Germany,

in the bricks of the palace on Capri,

where, one by one, he lost his family.

Or in the eerie luxury of his boats, found at the bottom of Lake Nemi.

And if what this tells us is that some of the myths may be true,

the paranoia, the excess, even the self-proclaimed divinity,

the rest, we'll never know.

Were the stories of murder and madness

created as much by Caligula himself to further a culture of fear?

Or were they spun just like his nickname, Bootikins,

to blacken his name and to justify his violent assassination?

Whatever the truth, it's in the story of Caligula

that all the elements of tyranny as we now recognise it

come together for the first time.

And perhaps that's why he's left such a powerful imprint

on our world.

For almost 2,000 years now,

Caligula has made people reflect on power and its abuse.

The man and the myth,

and to be honest, you can't ever quite separate the two, have raised

all kinds of questions about cruelty, excess, about adoration,

and about the delusions of an autocrat,

and about his fearful isolation.

But, for me, Caligula also turns the spotlight onto ourselves,

about what our own responses to tyranny should be.

Maybe there's a lesson. After all,

when that group of disgruntled army officers decided to rid Rome

of the monster, sure - they left him in bits on the palace floor -

but all they got was more of the same.

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