Original subtitles

This is the main gate of a great Roman city,

on the empire's northern frontier in Germany.

It advertises the presence and the impact of Rome.

And it's still here, 2,000 years later.

Rome was built to last.

But it didn't.

One of the biggest puzzles about the Roman Empire has always been

what caused its decline and fall?

Historians have been debating that one since the fifth century AD

and we still haven't agreed an answer.

There are all kinds of theories, from the sensible to the silly.

Was it the invasion of barbarian hordes?

Or was it galloping inflation?

Was it corruption, public and private?

Too much sex?

Or maybe too little sex?

Or was it the lead in the water pipes,

gradually sending them all mad?

Happily, this isn't a multiple-choice test,

and one thing's for sure, it's all intriguingly complicated,

so bear with me.

From its mythical origins...

..to the reality of empire...

..stretching from Britain in the north,

to the fringes of the Sahara in the south...

..Spain to Israel, the Nile to the Rhine.

The Roman world was more culturally diverse,

productive and connected than anything that had gone before.

We tend to joke when we say, "All roads lead to Rome."

But actually, they did.

It seemed like Rome had discovered the art of imperial longevity,

thriving not only by exploitation, but by creating citizens

and at the very top of the pile, the Emperor.

You probably have to kiss his feet.

But the Roman Empire was more vulnerable than it looked.

There was conflict and there was resistance,

both from the outside and within.

This was Romans attacking Romans.

So why DID the Roman Empire come to an end?

Or did it?

No-one's ever going to know for sure what caused Rome's decline.

It's not the kind of question that you can ever answer once and for all.

But I'm going unpick a story that makes sense to me.

And I'm starting at one of the most recognisable

and puzzling monuments in the Roman world.

The 115km-long Hadrian's Wall, that spans northern Britain.

Built in the second century AD when the empire was at its widest,

what its construction hints to me, is a shift in the way the Romans

saw the empire and what happened at its boundaries.

In some ways, Britain was Rome's Afghanistan.

The Romans always found it terribly hard to get

the upper hand, particularly in the north of the country.

It wasn't that there were loads of pitched battles

between Romans and barbarians,

but there were decades of terrorism and guerrilla warfare.

The wall must have been something to do with controlling that.

But it was never a straightforward defence against the enemy,

it was more a Roman statement.

This really is an aggressive structure,

ploughing through the country, from one side of it to the other.

It seems to me there's two things going on here.

First of all, it is a major symbol of Roman power

and it's speaking to both people out there to the north

and at those down there to the south.

But there's also a new idea of what an empire is that's at stake here.

They're starting to say, the empire has an edge, it has a boundary.

And they're doing that here and in other places in the empire.

This is the start of the empire being mapped.

And that made a big difference.

As we know now, the moment there's a physical barrier,

whether it's a wall, a fence or a river,

it doesn't just keep people out, it also entices them in.

And there was an extra urgency to that. When almost everyone inside

the empire was a full Roman citizen, almost everyone outside not.

It wasn't a simple stand-off between insiders and outsiders,

Romans and barbarians.

The frontiers of the empire were always pretty porous,

in our terms, and you even find so-called barbarians

serving in the Roman army.

All the same, it was a whole series of flashpoints that put

the empire on the defensive against invaders, against waves of refugees

and against economic migrants, and to be honest,

it was quite difficult to tell the difference between those three.

The effect of all that was somehow to turn the empire inside out.

The centre of things was now on the margins.

That's where more and more Roman cash was spent, it's where more

and more Roman resources were eaten up

and it's where the decisions that really mattered were taken.

In a way, the Romans on the frontiers, the soldiers

and the generals, became the key power brokers.

The change was dramatic.

In the third century AD,

emperors were usually raised to power by the legions,

with little or no reference to the authorities in Rome itself,

and they didn't last long, either.

Most of them barely had time to issue some coins

and put up some statues before they were gone,

often assassinated by the supporters of the next guy on the throne.

One of this lot was Elagabalus,

parachuted onto the throne by his granny

and an army legion.

If you believe the stories, he was a nasty piece of work,

making Nero or Caligula look like pussycats.

Bellissima!

He was particularly well-known for his flamboyant banquets.

A meal with him was an experience to die for.

And sometimes, literally.

The food was about as far-out as you could get.

Nightingales' tongues and ostrich brains, particular favourites.

But he was artful, too.

He was particularly keen on colour-coded banquets.

All the food in blue or in green.

But there were risks.

If you were at the bottom of the pecking order,

you didn't get real food at all.

You just got model food, in wood or plaster.

All you could do was look at it.

And on one occasion, he showered so many rose petals on his lucky

guests that they smothered and didn't get out alive.

The Emperor was a complete fashion freak.

He never wore the same pair of shoes twice.

He had his mum in the Senate

and he loved being pulled along in a wheelbarrow by naked ladies.

He even went so far as to change sex

and he had a vagina surgically constructed.

Now, this isn't all literally true.

For a start, Elagabalus was only 14 when he came to the throne.

At best, it's a fantasy about what it might be like having

a very difficult teenager as Emperor.

At worst, it's black propaganda, invented after he'd been deposed.

But there's a logic to it. It's a fantasy about a system under threat.

The idea that the man on the throne was completely bonkers

was saying more about the way the system was imploding

than about the man or boy himself.

But the Romans didn't just sit and watch it all happen.

'And the best way to explain how they tried to restore order...'

Prego, senora. Ah, grazie mille! Buon appetito!

'..is with another meal.'

This is called a Pizza Romana.

And one thing's for sure, no Roman ate it, because for a start,

they didn't have tomatoes.

But if you suspend disbelief for a bit, it's quite a good

way of visualising the problems the Roman Empire's facing.

The pizza is the empire.

Rome is the tomato in the middle.

Problem number one?

The empire's very big.

Communications across it, very slow.

Rome's here.

It's really...

weeks away from getting its commands out to the frontiers.

So what do they do about it?

Well, as usual, the Romans improvised.

They decided to cut the empire in two.

It's quite difficult, cutting an empire in two.

And you can even go further.

You can say...

divide the empire into three, with three joint emperors.

You can even divide it...

If you can cut it!

You can even divide it into four, with four joint emperors.

The advantages of this are obvious.

You get manageable chunks to administer.

One emperor for that, one for that, one for that, one for that.

The disadvantages are obvious, too.

This guy decides he wants to have this person's share

and so you get conflict.

And what looked as if it was kind of devolution

turns out to be a disintegration.

The other problem they deal with is what to do about Rome

and here we get another kind of devolution.

You get a series of mini capitals... These are the olives.

..for different parts of the empire.

That one, let's say, is in the east, that's Nicaea.

This is Trier, in Germany.

Ravenna or Milan, in Italy.

And those cities can be administrative centres

for the different bits, and that makes all of the kind

of problems of communication and so forth much easier.

What to do about Rome in the middle?

When all the decisions, really, are being made in these other capitals.

Well, the answer is that Rome stays looking lovely,

it stays being a grand symbolic centre,

but it's not really doing anything.

In a way, this poor tomato has become a bit of a white elephant.

The city of Romulus no longer controls the Roman world.

Of course, it remained hugely symbolic, but some emperors

ruled their slice of territory without ever even going to Rome.

One-man rule, established by the first Emperor Augustus, was,

for a time, devolved to multiple emperors in a divided empire.

And this is the grand imperial throne room

of the mini-capital at Trier in Germany.

It's a building with some powerful messages.

It's telling us, for one thing, that Rome was no longer

the centre of Roman power.

But in its modern reincarnation, there's a clue to an even

But in its modern reincarnation, there's a clue to an even

bigger revolution that was taking place within the empire.

It was later converted into a church,

and as we'll see, that was no accident.

Because there was something bigger happening than any of those

problems on the frontiers, mad emperors and rivalrous legions.

The entire Roman belief system was being challenged.

And to understand that, we have to go further back into Roman history,

to see how the relationship between the gods

and the Roman state had traditionally worked.

This is a Roman temple.

You wouldn't come here for services or to be preached at,

you wouldn't come to get married or to be part of the congregation.

The chances are, it'd be locked up most of the year anyway,

guarded by some grumpy custodian.

But if you did get inside,

one thing you certainly would have seen is a statue of the god.

That's the basic function of a Roman temple,

to house the divine image, and that's what temples

were often called in Latin - "aedes".

Houses.

And temples were everywhere.

So, why did they need so many?

Well, this one was put up to the god Hercules in the middle

of the second century BC,

almost certainly with the profits of Roman conquest in the east.

And that was a common pattern.

A general in the middle of battle would vow a temple to the god,

if that god would grant him victory, and when the general returns

to Rome successful, he uses part of the spoils to finance the building.

In a way, temples are public reminders of the gods'

support for the Roman state and they underline the axiom that Rome

can only be successful if it keeps the gods on its side.

And gods is, of course, plural.

It might seem obvious, but there were loads of them.

And to us, the interaction between them

and the Romans can look a bit contractual, even mechanistic.

The Romans didn't believe in their gods,

they didn't have internal faith in our sense.

They simply took it for granted that the gods existed

and would help them out,

so long as they fulfilled their side of the bargain,

by erecting temples or, above all, by sacrificing to them,

usually animals, whether bulls, pigs or sheep.

And we can glimpse how important that was in this once splendid

sculpture, now a bit stranded in a Roman backstreet.

Here, we've got a scene of sacrifice to the gods.

On the lower panel, there's a bull actually being slaughtered, and

above, the emperor is pouring some

kind of libation onto an altar.

You can find hundreds of scenes like this across the Roman Empire

and the point they're making is that one of the functions

of the emperor was to manage the relationship between humans

and the gods. Religion and politics were bound up together.

There's a decidedly public, a decidedly matter-of-fact side to all

this, but that doesn't mean the gods didn't also have a personal impact.

On the contrary, they permeated the lives of the Romans.

It was a world full of gods.

This collection of miniature gods and goddesses takes us

right into the world of personal religion. These are private objects.

There were thousands of them across the Roman Empire, in people's

pockets, on their mantelpieces at home, in temples and in shrines.

They're kind of like everything from fridge magnets to

objects of devotion, all rolled into one.

This was an incredibly complicated religious world.

We're not dealing here with 12 gods and goddesses,

sitting up on Mount Olympus, each with their own job to do.

Venus, the Goddess of Love, Mars, the God of War.

That's what I learnt at school, but it's very misleading.

This is much more a question of a whole range of different

divine powers which control the world in different ways

and help us make sense of it.

That might be questions of - where did human life begin?

Or much more practical things like - will I get across the sea safely?

In that case, you might have decided to turn to the god Neptune,

the God of the Sea, but equally, you might have approached Minerva,

who had to do with the craft of seafaring, or Hercules,

who protected humanity in their struggles against adversity.

Or you might equally have turned to Mercury,

the god who helped you get places and helped you make a profit.

This was an extraordinarily flexible religious system,

in which people made their own religious choices

and they created their own religious world.

Religion was fundamental for the success of the empire

and the Romans made sure their gratitude was on full display.

But the growth of the empire brought new

and different gods into Rome. Just as the Romans incorporated

new citizens from new conquered territories,

they incorporated divine citizens too.

One of these new religions, thought to originate in what is now

Iran, didn't have grand temples, at least not above ground.

This is a wonderfully preserved temple of the god Mithras,

on an absolutely standard pattern.

All across the Roman Empire, they look a bit like this.

It's dark, enclosed,

and it was almost as hidden away then as it is now.

It's actually all been done a bit on the cheap.

This marble floor looks impressive enough,

but it's obviously come off a Roman skip.

And up here, they've even made their little steps by cannibalising

some old inscription.

Using whatever they could lay their hands on,

they created an underground religious world, a cave,

which was thought to be an image for the cosmos itself.

This was a place where people came together to worship.

The worshippers would have reclined here, just as if they were dining.

Presumably, whatever ritual went on, went on in the middle.

To judge from the image of Mithras himself,

usually shown killing a bull, animal sacrifice was central, even if

other details are pretty mysterious.

What we do know is that it was entirely men, this was about the

most blokeish religion in the Roman Empire, which is saying something.

It was also a religion of initiation.

You went through a series of stages or grades of initiation,

getting closer all the time to a vision of the divine truth.

The best clues to the strange world of Mithras

comes from the imagery salvaged from several of his temples.

You've got Mithras himself,

plunging his dagger into the side of the sacrificial bull,

and he's wearing a very distinctively shaped Persian

hat, signalling that he comes from the margins or

outside of the Roman world and there's something, I think, about

the exoticism of all this which must have been part of its attraction.

But exotic or not,

it still fitted comfortably enough in the Roman world of polytheism.

Real problems began

when monotheistic religion came into contact with Rome.

The worship of just one god and the exclusion of all others was

something that went against basic Roman assumptions.

Judea was made a province of the empire in 6 AD.

People here had their own way of life

and a distinctive relationship to one god.

So when the Romans took over, with a very different

set of assumptions, a clash was almost inevitable.

A mixture of politics, local infighting

and religious conflict ended

when the Romans destroyed the temple in Jerusalem

and that triggered a six-year long full-scale Jewish revolt.

The end of that war came at a desert outpost called Masada.

In this remote spot, King Herod,

one of Rome's earlier allies or collaborators in Judea, had built an

extravagant palace, where he could dine and bathe in true Roman style.

He would be disappointed to know that the place is now

famous for much bloodier reasons.

The final showdown between the Jews and the Romans happened hours

away from Jerusalem, here in the middle of the desert.

There was a breakaway group of about 1,000 Jewish extremists,

that were terrorists in the eyes of some Jews as well as the Romans,

and they'd seized Masada and they were holding out there,

years after the temple in Jerusalem had fallen.

The Jewish rebels made this rock their base and eventually

met their deaths when the Romans caught up with them.

To understand what happened next,

I'm meeting historian Greg Woolf in the ruins of the old palace.

These forts look very impressive, laid out as they are below,

but at the time they were built, Jerusalem had fallen,

the temple was destroyed, there's no opposition anywhere else.

There was still a small group of people holding out up

here for years.

They're almost forgotten until a Roman governor decides

he really ought to sort it out and he sends the legions here and

so this is what we see here, it's a trace of a cleaning-up operation.

You can still make out where the forts and the siege wall are.

And at a weak point in the cliffs, a ramp was built for a battering

ram and the Romans broke through the rebels' defences.

One Jewish rebel, turned traitor, then Roman historian,

recorded what happened next.

Although his version of events has long been disputed.

We have this extraordinary story told by a very,

very unreliable source, who says that when the Romans got up here,

when they built their ramp,

when they came in, what they found was no living person.

Nearly 1,000 people who had been up here had, in some

kind of mixture of suicide pact and self-slaughter, had just gone.

There was nobody left here. There were piles of bodies

and enough food to show they could have held out for ever.

But if this is true, who knows? It's become a powerful modern myth.

So it's a story of heroic self-sacrifice for the cause?

Self-sacrifice and no surrender and that's what Masada means now,

no surrender.

Only a handful of bodies have ever been found here

and who they were is unclear,

but the story of rebels who preferred suicide to enslavement

lives on and Masada remains a symbol of Jewish resistance.

The conflict behind all this is often framed in religious

terms, but the truth is more complex.

You'd expect some kind of clash, wouldn't you?

Because you've got a culture in Judaism which insists that

there's only one god,

dealing with a Roman imperial power that insists there's lots of gods.

I mean, that appears irreconcilable. Yes.

Although there are things about what the Jews do that looks very

familiar to a Roman eye.

They perform animal sacrifice. They have a huge temple at the centre.

And perhaps most of all, it's a

religion grounded in one ritual landscape, one sense of place.

It's a religion of somewhere.

Which they can always manage that, can't they?

You can have a religion pretty much that is as weird to them

as you can imagine, so long as it sort of belongs to somebody.

So they're sort of happy with the goddess Isis

because she's the Egyptians' goddess.

The Romans didn't expect those they conquered to abandon their own gods.

Part of the point of polytheism is that it can accept

and incorporate new and different divine powers,

but they did expect them to recognise

the relationship between the Roman state and religion.

For the Jews, it's much more difficult to accommodate

the Romans because their own history by now is a history of being

subjected to one empire after another

and being subjected to persecutions of different kinds and so,

it's much more difficult for the Jews to fit the Romans into the

system, rather than the Romans to fit the Jews into their system.

And that's where things broke down.

Over the next 200 years,

there were more bloody chapters in the history of Jews and Romans,

but to see it from the Roman point of view,

what's just as remarkable is how far they managed to accommodate

Judaism within the empire.

They used taxation as a means of control,

Roman emperors received delegations

and complaints from Jewish communities,

individual Jews progressed high up in the Roman administration,

and in many ways Judea was a prosperous little Roman province.

But for one offshoot of Judaism, and that's Christianity,

it was to be a very different story.

In the turmoil of conflict between Rome and Judea,

one Jewish Rabbi had developed new ideas.

His name was Jesus.

The "sayings of Jesus," as they were called,

were only written down later,

but it's clear enough that for the Jews, he was preaching blasphemy.

And at the beginning at least, for the Romans,

he was just another troublemaker.

However exactly the story went, he was arrested, put to trial

and sentenced to death, Roman style, by crucifixion.

The Romans must have thought - problem solved.

But it was only the start.

It was near here that Jesus came to be crucified,

probably on some charge of civil disobedience.

It's very hard to know exactly what was going on because the story

has been rewritten and reinterpreted and embroidered ever since.

But we can be fairly certain that the real Jesus was

the leader of some small Jewish splinter group

and in the decades after his crucifixion, he became...

He was almost reinvented as the founding symbol of a new

religion which attracted followers more widely across the empire.

There weren't, to start with, all that many of them

and they believed a variety of different things that we wouldn't

recognise now as Christian.

But at the core of it all, there was

a new ideology that was challenging, from within the empire itself,

old Roman certainties about how the world worked.

Today, Christian pilgrims from all over the world flock to

Jerusalem to visit the spot where Jesus was buried,

in the appropriately named Church of the Holy Sepulchre.

Although, to call it a church is an understatement.

Under one roof,

a bewildering array of Christian sects fight to be heard.

And the biggest queue of pilgrims

and curious tourists is by the shrine that surrounds Jesus' tomb.

This is the holiest site in Christendom.

The idea that Jesus rose from the dead would have been

the least puzzling part of Christian teaching for most Romans.

There was a combination of far more radical ideas than that.

It wasn't just that there was only one god,

those who followed Jesus could take no part in sacrifice,

and they were to prepare themselves for the Kingdom of God, which

transcended the earthly power of Rome and which might be coming soon.

Add to that the very strange notion that poverty was a virtue,

not a misfortune, and some pretty hardline views about sex,

and it's not difficult to see how some Romans might have been

curious, even attracted to Christian teaching.

Many others would have been baffled or affronted by what must

have seemed like an assault on their world order.

Christianity flew in the face of what Romans had traditionally

thought religion was all about.

And that contradiction may be one reason why Christianity was

initially slow to take off.

But when it did, it exploited the very network of communications

that linked the Roman Empire.

One of the key figures in spreading the word was a small-time

Roman salesman from Turkey, better known as St Paul.

Jesus himself wasn't a big traveller, but Paul not only

got everywhere across the eastern Mediterranean,

he also used the long-distance mail as a way of broadcasting to

far-flung Christian communities

and the letters he wrote are still part of the Bible.

Corinthians, that's the letter he wrote to the Christian church

at Corinth and he's writing to the people of Thessaloniki, to the

people of Ephesus, the Ephesians, and to the Christian church in Rome.

They're part pep talk, part instruction,

and not all of it is entirely to my taste.

"Man is the head of woman," he says. That's never going to be my motto.

But what does strike me

are the geographical horizons that these letters display.

He talks about being in Macedonia

and going to travel to Ephesus and then move on to Corinth.

It's the connectivity of the Roman Empire that these

Christians are exploiting.

Christianity was born within the Roman Empire

and the people who became its followers rode on its connectivity.

In port towns like Corinth, and Thessaloniki,

you could find goods, work and a new spiritual guide.

The empire's trade routes became Christianity's broadcasting service.

200 years after Jesus' crucifixion, there were small groups

calling themselves Christian across the empire and in Rome itself.

Though there were not many in total, perhaps 200,000 out of an empire

of 50 million, and there were very different shades of Christian too.

This is a tombstone that really parades its Christianity.

And the keyword is this, written in Greek, it's "Icthus,"

which means fish, but it's not just a fish

because the letters of that word are also the first letters of a famous

Christian slogan, reading,

"Jesus Christ, the Son of God, our Saviour."

Now, why they used that slogan is not absolutely clear.

They might have been wanting a bit of secrecy,

but if so, Icthus isn't a terribly clever disguise.

It's much more likely that this is an attempt to represent God

and to wonder how God should be represented.

They're thinking about encoding God in language and in visual symbol.

But there's more to this and there's more gods in this tombstone.

Up here, these two letters, DM, stand for Dis Manibus, to the

gods of the departed spirits,

the absolutely classic traditional pagan gods of the dead.

So, here we've got both Christianity and paganism on the same stone

and it's a wonderful encapsulation of just that blurry boundary

between Christianity and paganism in the first Christian centuries.

Most Christians in the Roman Empire probably inhabited that

blurry boundary.

But a few were much more hardline, overachievers,

extremists you might almost call them,

who came into conflict with Roman authorities and went

to their deaths for refusing to sacrifice to the traditional gods.

One spring day in 203 AD, a young Roman woman,

the mother of a small baby,

was thrown to the wild beasts in an amphitheatre not unlike this one.

She was taunted, she was whipped, and maimed by the animals,

but not killed. A gladiator came to finish her off.

After one painful mishit,

she calmly took his blade in her hands and guided it to her throat.

Her name was Vibia Perpetua and her only crime was to be a Christian.

This was Romans attacking Romans.

We tend to assume that Romans loved the spectacle of Christians

thrown to the lions in the amphitheatre.

But it really wasn't quite that simple.

An amphitheatre was a highly ordered microcosm of Roman society.

The spectators sat in a rigid hierarchy,

according to their social place.

You couldn't just choose to shell out for a good

seat on the front row like you can now.

And the victims in the centre, the slaves

and the condemned criminals, were, by definition, outsiders.

They were never intended to be young Roman mothers like Perpetua,

one of their own.

It's hardly surprising that her prosecutor tried to get her

to think of her young baby and to recant her faith.

And it's hardly surprising that the crowd,

as they watched Perpetua die, both jeered and shuddered.

Perpetua's story of pious resistance

and brutal execution has become part of the Christian

narrative of good against evil.

Where many non-Christians must have seen stubborn,

self-willed self-destruction, Christians saw in martyrdom

a powerful advertisement for their faith.

Long after their moment in the arena, stories of the killing,

the torture and the excruciating suffering were told

and retold in meticulous and sometimes lurid detail.

The bravery of the martyrs in the face of sadistic cruelty

seemed to validate the faith for which they had died, and to offer

other Christians an example they might glorify, though not follow.

Quite why the Roman authorities chose to send them

to their death remains something of a puzzle.

That's largely because almost all the evidence

we have comes from the Christian Romans themselves.

It's an extreme example of history being written by the winners.

If we try to see it from the side of the Roman authorities,

the fact that the Christians refused to sacrifice threatened to

disrupt the good relationship between the state

and the divine powers, which ensured the success of the empire.

It was pure treachery.

In the middle of the third century, less than 50 years after Perpetua's

death, one emperor decided to bring things back into line

and to restore order with a piece of paper.

These are scraps of papyrus from a Roman waste paper

basket in the province of Egypt

and they're some of the most important things ever to have

been found in a waste paper basket

and it's also a wonderful example of Roman bureaucratese.

They are personal certificates proving that their owner has

sacrificed to the traditional gods.

The gist of the message is up here, saying so and so has sacrificed,

it's been witnessed here, and one of the witnesses has signed.

His name was Hermas.

And this guy's actually signed several of these certificates.

The reason why he's done that is

because the Emperor Decius had ordered that

everybody in the empire should prove they'd sacrificed to the gods.

This is often treated as a centralised

persecution of the Christians because, of course, true

Christians couldn't sacrifice to the traditional gods.

And we know, in fact, that some of them didn't

and supposedly went to their deaths.

But even Christian writers tell us that many of them,

and this is I think where I would have been,

either sacrificed anyway or just kept their heads down.

What's going on in the emperor's mind is also rather different,

I think.

I'm sure he's not planning more bloody

spectacles of Christians versus lions.

What he's wanting to do is to ensure that every single

one of his subjects signs up publicly to the

institution of sacrifice, which is

the ritual that ensures that proper relationship between the Roman

state and its gods, and ensures Roman success.

In a way, this is a clumsy and rather heavy-handed attempt to

restore political and religious order to the Roman world.

His project didn't last long and neither did he.

Decius wasn't dealing only with the Christians,

but between the invasion of the barbarians and internal rivals, his

reign only lasted two years and he ended up killed on the battlefield.

It would have been beyond the wildest dreams of Perpetua

and those who died like her that in less than 100 years,

Rome would turn in exactly the opposite direction.

After a century of chaos, one emperor made a pact with

the very religion that looked as if it was undermining the empire.

His name was Constantine and, eventually,

he became once more the sole emperor

and aligned his power with that of the sole god, the Christian God,

that is.

These fragments are what's left of a colossal

statue of the Emperor Constantine.

It can't all have been in marble, it could never have stood up if it was.

We have to imagine a brick and a bronze core

and these bits sort of stuck on the end.

It's an entirely new vision of imperial power.

Of course, there had been colossal statues of emperors before.

But just look at that face...

..superhuman, staring, almost abstract.

This isn't an emperor who could conceivably be one of us.

This is an emperor we have to worship.

We probably have to kiss his feet.

Constantine is a striking mixture of the old and the new.

He comes to power in civil war, he celebrates a triumph,

he acknowledges divine assistance

and he has a big building programme in the city of Rome.

All that's very traditional.

What's new is that the God whose help

he acknowledges is the Christian God.

And what he builds in the city is not temples but it's churches.

We really don't have a clue why Constantine became a Christian.

It might have been a sincere spiritual conversion.

It might have been a calculated decision to back what

looked like the winning side.

The political logic of this, whatever is going on

inside Constantine's head, is that circle has been squared.

The universal empire, instead of fighting the universal church,

has done a deal with it.

From now on, empire and church are going to walk side by side.

One way of seeing this is as a revolution.

Fundamental aspects of being a Roman have changed.

Hierarchy, faith, morality, sex... But in another way,

Constantine has reinvented the original model of Roman power

around a new God.

And he sealed the deal by building a new capital,

which eventually became the new Rome.

Constantine's city was Constantinople.

We now know it as Istanbul.

It was here that he ordered his own versions of some of the major

buildings of Rome.

The site of Constantine's Hippodrome,

his Circus Maximus, has been preserved, complete with

a few of the monuments that he and later emperors placed along its centre.

Robin Cormack, my tour guide and husband,

knows more than me about the art and culture of the Eastern Empire.

I think this is a really impressive monument.

They're really proud of it.

The amazing achievement is to get that obelisk from Luxor

onto this stand.

And they were so proud of what they'd done

that they have two inscriptions saying how difficult it was.

And they have the pictures of the putting up of it.

We can see the ropes here to winch it up.

This is Roman technology as it ever was. At its best.

'But why did Constantine choose to build his city here?'

It only happened because he had won his last

battle against his rival Roman emperors and it is a victory city.

He looked around, he chose a city near to where the battle was.

The city of Byzantium.

And he turned it into a massive, powerful new city,

named after him, Constantinople.

So, it shows he is now the single Roman Emperor.

So, did it feel like a specifically Christian city?

Did it feel different?

No, it looked like a Roman city with all the trappings.

And what he did do was bring lots of pagan statues here,

so that you've got those in the Hippodrome and elsewhere.

So much so that there is the famous saying that this city was

built up by denuding all the other cities of the Roman Empire.

It must have been a bit odd to see an emperor

who is sponsoring Christianity, decorating his city with pagan gods,

great works of art, that he

has sucked in to decorate it from all the other bits of the empire.

Yeah, well, he's a powerful emperor, isn't he?

This is a display of power.

He made this a traditional Roman city with all

the features that the biggest city he knew, Rome, had.

They didn't call themselves Byzantines,

they called themselves Romans

and they were absolutely convinced that they were the Roman Empire.

In fact, here in the East, the Christian Roman Empire lasted

right up to 1453, when the Ottomans conquered Byzantium.

In the West, it was a different story.

Rome was still Rome but it was more a showcase of architecture

and culture than the capital of power.

But the northern frontiers were more porous than ever.

Outsiders pushed in.

And even if it was now a hollow symbol,

the city of Rome was still a prize.

Driven by the Huns, various tribes, like the Visigoths,

the Ostrogoths and the Vandals, moved towards the Western Empire.

The legendary "sack of Rome" didn't happen once, but three times.

Roman armies were defeated, citizens were killed

and the city itself was looted and pillaged.

The very words "barbarian" and "Vandal" now conjure up

a picture of wanton destruction of all that is civilised.

But that popular image, powerful as it is, is quite unfair.

This is a wonderfully vivid 19th-century attempt to

picture the barbarian hordes in action, destroying the city of Rome.

Long hair, funny topknots, plaits and moustaches.

And a couple of them are trying to topple

one of the symbols of imperial power.

Their mates are getting their torches ready

to set the place ablaze.

Actually, the world of the new West was nothing like this.

It's true that political unity had collapsed

and there was plenty of destructive military conflict.

But what emerged was a series of rival powers,

who were, in effect, mini Romes,

who were trying to buy into the prestige of Rome

and Romanness, rather than trying to buy out of it.

They sponsored Latin poetry,

they developed the traditions of Roman law, and they were more likely

to be restoring the monuments of the Roman past,

not trying to pull them down.

The empire, in a political sense, had gone.

But the cultural hegemony of Rome remained, even in the West.

These people were not Romans. But they were imitating Rome,

much like many modern empires have done ever since.

With these barbarians imitating the Romans so closely,

can we really call it the fall of the Roman Empire?

How do you decide how or when an empire starts or ends?

What counts? Is it territorial control?

Is it law or culture? Is it the Roman brand?

There has been an enormous transformation and, in many ways,

this is no longer the empire that looked back to Romulus,

with his definition of what it meant to be a Roman.

It's a transformation, a revolution, almost,

that I see clearly here,

in what was once Rome's mini capital of Trier, in Germany,

in the grand Imperial Throne Room, that later became a church.

The conclusion I come to is that the real heir of the Roman Empire

was Christendom.

Not an empire of political domination, or not only that,

but an empire of the mind.

And, in its own ambitions, at least,

still an empire without limit.

From the mythical beginnings of Romulus and Remus

to the political and military systems that enabled expansion,

it's the image of Rome that, for better or worse,

has acted as a benchmark for so many later empires.

Britain, Russia, America, even Nazi Germany,

have all tried to recreate what they saw as the glory of ancient Rome.

And they haven't avoided some of the same problems, dilemmas

and conflicts of imperial rule.

Today in the West, we still wonder where our boundaries lie

and what limits should be placed on inclusion.

We've inherited the Romans' ambivalence too -

questioning whether the ends ever justify the means -

the tears alongside the victory parades.

2,000 years ago, the Roman historian, Tacitus,

offered one image of the fallout of Roman conquest.

"They make a desert," he wrote, "and they call it peace."

I first read that when I was a bit of an awkward teenager,

and I still remember the moment.

Because it was the first time that the Romans

actually seemed to speak to ME.

It was the brutal clarity of it that was so striking.

And I guess that ever since, however much I've admired the Romans,

however much I've been repelled by them,

they have always held my attention.

For me, it's the conversation that we can still have with the Romans that's so important.

The conversation that makes us think harder about ourselves

and about the ideas and problems that we have in common with them.

There's a little bit of the Romans in the head of every one of us.

And that's why Rome still matters.