The Mystery of Rome's X Tomb

Beneath the streets of modern-day Rome lies a network

of interconnected tunnels that stretch for hundreds of kilometres.

These are Rome's catacombs.

They are over 1,500 years old

and they contain many of Rome's ancient dead.

In 2003, deep within this subterranean labyrinth,

a bricked-up tomb was discovered, unlike anything seen before in Rome.

IN FRENCH:

This was an ancient mass grave,

piled high with thousands of skeletons.

As a classical historian,

I've studied burials across the Roman world

and I've never seen anything like this.

Who were these people, what did they die of

and why are they buried here in this extraordinary manner?

For the last ten years,

an international team have been trying to find out.

Combining archaeology with cutting-edge science,

they're looking for clues in the layout of the tomb...

..in personal possessions,

and in the bones themselves.

Joining the archaeologists is one of the world's leading specialists

in decoding ancient DNA.

He's trying to find out how these people died.

This might be related to a catastrophe,

to some kind of pandemic, to some kind of disease spreading.

A chance find, a tomb that confounds all expectations,

and multiple mass deaths.

This is the mystery of Rome's X Tombs.

Rome's catacombs have been explored

and excavated for centuries,

and by and large, their use, their layout, their architecture

are fairly well understood,

but then a chance discovery in one of these catacombs

opened up a whole new mystery.

This is the Catacomb of St Marcellinus and St Peter.

It was here, in the summer of 2003...

..a burst water main caused the roof in one of the tunnels to collapse.

The Vatican's Inspector of Catacombs in Rome,

Raffaella Giuliani, was called in to investigate.

The first thing they found was the remains of a mediaeval fresco.

The painting is believed to show

the two fourth-century patron saints of the catacombs,

Marcellinus, a priest...

..and Peter, an exorcist.

They appear to be standing guard over a burial chamber.

But nothing could have prepared Raffaella

for what lay hidden behind the fresco.

They had uncovered a mass grave.

The burial site was located in

an area of the Vatican's underground mapping system labelled "X".

They came to be known as the X Tombs.

To find out if this was the last resting place

of hundreds of Christian martyrs, the Vatican sought specialist help.

A team of French archaeologists

were called in, led by Dominique Castex...

..and Philippe Blanchard.

Both are highly experienced

in excavating ancient mass graves.

Wow.

As excavations began,

six more chambers were uncovered,

each piled high with bodies.

The tombs were arranged on three separate levels,

all located around a central hub.

We need to completely forget these modern walls,

which are working as foundations to stop the six metres or so of rock

above our heads from collapsing on us. This is the crucial bit.

This is the largest of the burial chambers,

and the archaeologists estimate there's just under a metre,

about 80 centimetres left of compressed bodies still to excavate.

There's another tomb there

that was full of bodies the archaeologists have now removed,

and there's another one, two, three burial chambers behind us,

so when we stand here,

we are surrounded by chambers of mass death.

Picking their way through the bones,

a few personal possessions came to light.

A pair of earrings...

..a hairpin...

..and a small black ring.

They also unearthed a few coins.

Just incredible.

The bones themselves revealed more clues.

OK...

The fact the skeletons were still intact,

with very little soil between the layers of bodies,

suggests that large numbers were buried here at the same time.

This has to have been something of a mass death moment,

what archaeologists call a crisis event,

multiple people dying within a very short space of time.

But was this one single event or a sequence of events?

To investigate further,

the team made a detailed study of one of the tombs

where all the bodies had been excavated and accounted for.

By digitally restoring the flesh to the bones,

a computer programme was used

to work out the original volume of the bodies.

This study suggests

these are the victims of a series of mass death events.

Currently, the archaeologists estimate the tombs contain

the bodies of around 2,500 people.

This is an incredibly unusual discovery -

tombs packed full of bodies layered on top of one another.

You just don't expect to find this type of burial

in a Roman catacomb.

I've studied the way the Romans buried their dead,

and it's clear that they had great respect for their deceased.

Burial in Rome was governed by two guiding principles.

The first was, you couldn't be buried in the city,

but the second was, you didn't want to be buried too far from the city

because you wanted your family to visit your tomb,

but perhaps more importantly, you wanted to show off.

This is the ancient Via Appia, one of the main roads out of Rome.

But every road outside the city walls

would have been crammed with tombs like these.

It was of Dionysius of Halicarnassus in the first century BC

that said the endlessness of tombs on the roads leading out of Rome

mirrored the endlessness of the Roman world itself.

But as the population of Rome expanded

during the second and third centuries AD,

the space available became increasingly limited.

Now, given the persistent desire amongst Romans

to be buried in suburban soil, you can see how very quickly

it became a pressing problem what to do with the dead,

and the solution, as far as the Romans were concerned,

was to go underground.

Rome was built on a soft, volcanic rock called tufa,

which could be carved out by hand.

These sprawling subterranean cemeteries grew rapidly under the city,

but they look quite different to the X Tombs.

Despite the fact that the corridors in a typical catacomb

meander every which way,

the layout of the dead was actually fairly regularised.

You had your individual tombs called loculi,

but I always refer to them as bunk beds.

There's still the bones of one poor individual left there.

And if you wanted something a bit more special

then you could have a cabicula,

a bedroom for the entire family to be put to rest on.

What was so good and so new about catacombs

was their limitless potential for expansion,

and as a result, inclusion,

which made them really popular with communities, be it pagan, Jewish,

or indeed, most importantly,

with the increasing number of Christian communities in Rome

during the third and fourth centuries AD.

And over time, as a result, they became a burial place,

not just for ordinary Christians,

but for their saints, their popes and their martyrs.

As excavations continue, the bones from the X Tombs

are removed and kept in a makeshift storeroom for further analysis.

So far, the French team have made a detailed study of around 500 bodies.

They're starting to build up a picture of who these people were.

SHE SPEAKS IN FRENCH

From the pelvis bones, they can tell

there is a mixture of men and women.

The size and stage of development of the femur bones

also gives an idea of their age when they died.

These people certainly didn't die of old age.

But are there any signs of trauma?

If they were Christian martyrs

or died a violent death,

you'd expect to see evidence on the bones.

None of the bones show any signs of trauma

that one would expect if someone had been crucified

or, indeed, if they died in battle in some sort of massacre.

So who were they?

Why were they buried down here like this? And when did they die?

One way to establish a possible date for the tombs and their occupants

is to study the few personal belongings uncovered with them.

The earrings were made from fine gold.

They have a design that became popular in the first century AD.

The ring was found to be made of jet,

a material Romans thought had magical powers.

Studying its chemical composition,

the archaeologists have concluded

it came all the way from Whitby, North Yorkshire,

in the third century AD.

Then there were the coins,

possibly left as payment to enter the afterlife.

Their age is much easier to establish.

The oldest coin is of the tenth emperor, Titus,

dating from AD 79 to 81.

The wife of the Emperor Antoninus Pius features on another,

as does the Emperor Marcus Aurelius,

both dating from the second century AD.

The last coin was of Emperor Gordian.

It's a rarer find than the others.

He only reigned for three weeks in AD 238.

Coins are fantastic.

They really help us narrow down the range, but there are caveats.

You carry coins around in your pocket for a long time.

They exist in circulation for ages, and the archaeological contexts here

in which these coins were found are not secure.

To try and get a more accurate date for the bodies,

the archaeologists wanted to test the bones using carbon dating.

But this proved quite difficult.

Carbon dating works by comparing the ratio of two forms of carbon,

carbon-12 and carbon-14.

When you die, any carbon-14 decays over time to become nitrogen

but the level of carbon-12 in your cells stays the same.

Over time, the ratio between the two forms of carbon changes

and it's this that gives you the date.

The breakthrough here is that the different chambers of the X Tombs

came back with different results.

The bodies from the two larger chambers

date from the second and third centuries AD.

But some of the bodies from the smaller tombs appear to have died

in the first century AD.

These dates suggest the first burials took place here

possibly up to 200 years before work began

on the surrounding Catacomb of St Marcellinus and St Peter.

The fact that these tombs pre-date the catacombs that surround them

raises the intriguing possibility that this could be the original core

from which the catacombs later expanded outwards.

This is an exciting revelation.

The X Tombs could be among the oldest underground tombs

found anywhere in Rome.

The dating provided by the coins and the bones and the other finds

indicate that these people died between the end first century AD

and the early part of the third century AD.

Now, that period of time in Roman history

was, by all accounts, a golden age.

Some of Rome's finest imperial buildings

were completed at this time.

The Colosseum...

..great bath complexes...

..and ever larger public forums.

The 18th-century British historian Edward Gibbon described it as,

"The period in the history of the world during which

"the condition of the human race was most happy and prosperous."

The people of the X Tombs were living at the centre

of a vast and powerful empire.

At its height, the Roman Empire spanned three continents,

five million square kilometres,

and its territories stretched from North Africa, Egypt,

the Middle East, Asia Minor,

across Europe and, of course, up to the border with Scotland.

And at the very heart of it was Rome,

Caput Mundi as they called it, the capital of the world.

The city was a mixture of cultures and traditions

with trade links that spanned the known world.

In the markets of Rome, you could find anything - copper, gold,

olive oil from Spain, cotton, wheat from Egypt,

tin from Britain, iron from Germany,

and more luxury products from further afield, like silks from China

or gems, pearls, spices from India.

Rome was a multicultural city

full of people and products from around the Empire and beyond.

This was the world's first metropolis,

with a population of over a million souls.

And the people of the X Tombs lived, and died,

in this cosmopolitan melting pot.

At their lab in Bordeaux, the French team are searching for more clues

to the possible identity of these people.

Kevin Salesse is analysing the chemical make-up

of the bones and teeth in a process called isotopic analysis.

This looks at the various atomic forms, or isotopes,

of chemical elements like oxygen and carbon found in organic remains.

The minerals in your teeth are set when you are a young child

and they don't change throughout your life,

whereas your bones keep remodelling themselves,

so they tell us about where you spent the last part of your life,

and by comparing the two,

we can find out whether these people were originally from Rome

or whether they came from elsewhere and migrated to the city.

In a second study, Kevin is able to explore

what sort of foods they might have eaten.

Their bones reveal a diet rich in meat and fish,

more than found in other communities in Rome at that time.

These people must have been fairly wealthy.

What's coming through very strongly in the archaeological analysis

is that the people of the X Tombs were not from Rome.

They came to Rome, but where they were from initially,

that's a question the archaeology is still struggling with.

There are some indications it may have been central Europe,

but also from elsewhere.

This doesn't seem to have been a homogenous population,

all from the same place, but they came to Rome,

they lived in Rome, and they died all together in Rome.

The French team are starting to build a picture

of who these people were

and how they lived, but they also want to find out how they died.

We know they weren't martyred.

We know from the dating that bodies were deposited here

possibly over a 200-year period.

We also know they were carefully packed in,

several layers deep at a time...

'..and that there was a series of separate mass burials.'

What the archaeology is showing us is fascinating,

that piles of bodies were put in these tombs

on top of already partly decomposed bodies,

so what we've got is waves of mass death.

We know it wasn't massacres,

so the best hypothesis for what could have caused this

has to be disease.

Disease was rife in the capital,

from tuberculosis to typhoid,

leprosy to malaria.

During the time of the X Tombs, diseases like these

are thought to have killed over 30,000 residents each year.

Much of this was down to living conditions.

Most of Rome's citizens

lived in the world's first high-rise apartment blocks.

They were called insuli, or islands,

and there were thousands of them, densely packed into the city.

This is the Insula dell'Ara Coeli. It dates from the second century

and would have stood at at least five storeys tall.

Down there is the Ancient Roman ground level.

That's where the floor was and the first levels, the shops and inns,

and then as you go up, you get the private apartments,

but you know what? You wouldn't want to be in the penthouse here.

The lower floors were rented to wealthy tenants.

The upper levels were for the less well-off.

The apartments were smaller,

the number of people in each room increased,

and living conditions were just awful.

The Roman writer Martial talks about a chap who had to run up 200 steps

to get up to his apartment. What could he expect when he got there?

Well, not much. Cramped living conditions, dirty,

probably a leaky roof, vermin,

families, groups of labourers, all squeezed into these spaces.

I mean, to call these places homes is overkill.

They were a place to put your head down at night.

Not a very pleasant one, even then.

Aqueducts brought in fresh water

and the city had an impressive drainage system,

but the people of Rome still lived in filth.

All rubbish basically just got shoved in the street

and then the public system of fountains washed it into the drains.

But then, well, frankly, there's the poo.

At its height, the population of Rome, it's estimated,

was producing 50,000 kilograms of excrement a day.

And none of these apartments were connected directly to the drains.

You had to take your chamberpot and get rid of it.

Likely as not, straight out the window.

The people of the X Tombs may have lived during Rome's golden age,

but the streets of the capital were more like an open sewer.

Disease raged through the city.

And there was no escape,

even at the famous baths.

The Romans loved their baths.

It was a great place to relax, soak, have a massage,

scrub down, chat with friends, or catch up on the gossip.

It was an incredibly important part of what it meant to be Roman,

and it was a practice enjoyed by everyone,

from the emperor all the way down.

The people of the X Tombs would have certainly gone to the baths.

They were part of the social glue that bound all Romans together.

The baths were attended by rich and poor, young and old,

healthy and diseased. In fact,

we know that Roman doctors actually prescribed a good soak in the baths

for all sorts of ailments, so if you had everything from boils to rabies,

from diarrhoea to tuberculosis, you came to the baths.

Poor people who didn't have a slave to rub them down

were encouraged to rub themselves against the walls.

The Roman writer Pliny the Elder

noted that scrapings taken from walls had warming properties.

Long before antibiotics, these scrapings were prescribed

in ointments to soothe sores and cure abscesses.

The sick and the healthy bathed together

because the Romans simply had no real idea of how disease spread.

The only thing that seems really to have bothered them

is seeing the physical signs of disease,

so if you had pus-filled boils or weeping sores

then they asked you to keep your clothes on while in the bath,

or sometimes they just put all the lamps out.

The baths really were the perfect place to catch a disease.

New strains of disease were constantly being brought into the city

by traders, migrants and soldiers.

You can easily see how the people of the X Tombs might have succumbed

to waves of infection.

To try to find out what disease might have killed them,

the French team have drafted in

a world expert in reconstructing ancient DNA.

Johannes Krause is a professor of paleogenetics.

His previous work was on the Black Death

which struck Europe in the 14th century, killing millions.

By extracting DNA from bones from a mass grave site in central London,

he proved that the Black Death was caused by the bubonic plague.

Here in the X Tombs, he faces a greater challenge.

The bones are much older. There may be very little DNA left behind

from any disease-causing microbes, or pathogens.

So what we want is the genetic material of the pathogen itself,

so we are trying to find places in the skeleton

that still might have the pathogen DNA preserved,

and what we have found is,

the best container for the genetic information are actually teeth.

How do you pick the particular teeth that you're going to work with?

We try to identify teeth that are still intact,

that don't have a crack or some hole in the surface.

And inside those teeth, we might have a little bit of dried blood

where the pathogen DNA might still be present.

So we can actually see that the jaw's just sticking out here,

you can actually see the teeth here being exposed,

which is perfect to actually get in here.

-Yes, yes, that comes out.

-Perfect.

-Look at that.

-Wow. You can see how wet that is as well.

-That's a molar from the left lower jaw.

-OK.

The teeth are photographed, catalogued and bagged up,

ready for transportation back to his lab in Germany.

Hopefully, we have a little bit of the pathogen DNA

that we can also get out of those teeth

and then reconstruct the DNA, reconstruct the entire gene.

Johannes believes that some of the people here in the X Tombs

might have been killed by one of the most virulent epidemics

ever to strike the Roman Empire.

This devastating disease was first recorded around AD 165,

when the Empire was ruled by two brothers.

It was called the Antonine Plague

because of the family name of the two ruling emperor brothers,

Marcus Aurelius and Lucius Verus.

Now, the origins of this plague are shrouded in mystery,

but there are reports that it emerged in the East,

where in the early 160s AD,

Lucius Verus was campaigning against the Parthians

on the eastern frontier of the Roman Empire

in what is today's Iran and Iraq.

A contemporary account from the pages of the Historia Augusta

tells us, "A pestilent breeze arose in a temple of Apollo

"from a golden casket which a soldier had cut open

"and it spread thence over Parthia, and the whole world."

The disease swept through the Roman Army, just at the time

when the Empire was challenged by invasions from the North.

In 168 AD, the emperor brothers came here,

to Aquileia in northern Italy, and Aquileia was a major trading centre,

but it was also a major military centre, and it was to here

that many of the Roman troops had been pulled back from the East,

and it was from Aquileia that the emperors wanted to mount a campaign

to push back invading tribes from the North

that were threatening the Italian frontier.

But when they got here, the emperors realised that the real problem

wasn't the invading tribes. It was the plague.

Army regiments would camp near towns and villages,

and soldiers often returned home on leave.

It wasn't long before the Antonine Plague

passed into the civilian population.

The Roman Empire was a vast, integrated, connecting trading network

which also contributed to the plague

being able to spread so far so quickly.

It was in Italy, it was in parts of central Europe, it was in the East,

it was in Egypt, there's even one report it made it as far as China.

And of course, as the saying goes, all roads lead to Rome.

When the plague struck the capital, there was panic and public hysteria.

Priests were summoned and religious rites performed to purify the city.

The people of the X Tombs would have been vulnerable,

just like everyone else.

According to Roman consul and writer Dio Cassius,

2,000 people often died in Rome in a single day.

In his books, the emperors' physician Galen described

some of the symptoms of the Antonine Plague - a fever, a rash,

diarrhoea, foul-smelling faeces,

an ulceration of the windpipe and dry, pustular eruptions on the skin.

No-one knows for sure

what actual disease was responsible for the Antonine Plague.

We know it claimed more lives than any previously recorded epidemic.

Across the Empire, something like five million people were killed,

up to a tenth of the entire Roman population.

The plague struck in waves that lasted from AD 165 to 180,

then again in 189.

It's entirely possible that some of the people in the X Tombs

living in Rome at that time

were killed by this disease that shook the Empire.

In his lab in Germany, Johannes and his colleague Kirsten Bos

are trying to extract DNA from the teeth samples taken from the tombs.

I drilled out the pulp from inside the tooth, which is now powder.

The powder now goes into a solution

where the DNA gets released from the bone.

So, our answer could be in that tube?

I hope so very much.

This process creates a mixture of billions of DNA molecules.

It's a cocktail containing all manner of genetic material,

but mostly soil microbes, plants and fungi

that were present in the tombs.

It's kind of like looking for the needle in the haystack,

so you have billions of molecules that we get out of those teeth

and maybe just a few hundred come from the pathogen,

so there's a lot of sorting and then there's a lot of puzzling.

To isolate any fragments of DNA

left over from bacteria or viral pathogens,

Johannes has adapted a technique known as DNA hybridisation capture.

He calls it fishing.

On this glass slide

are 100 short, single strands of synthetic pathogen DNA.

They include the genetic codes of everything from smallpox to measles,

typhus to bubonic plague.

The cocktail of DNA from each tooth is then added to the slide.

The synthetic strands now act as bait

to hook out any actual pathogen DNA from the solution.

DNA has this double strand, where you have the bases facing each other

and there's always this A facing with the T,

and you have the G facing with a C.

-And this creates that famous double helix...

-Exactly.

..that everyone knows, the kind of picture of DNA.

And just if the right sequence kind of matches the opposite sequence,

those DNA fragments will actually bind and form the double bind.

If they don't match, they will not come together.

It's like a magnet, basically.

It only kind of pulls the DNA together if the strands match.

-So only pathogens will bond?

-Only pathogen DNA would bind here.

But Johannes is pushing this technique to its limits.

It's never been used to fish for so many possible causes of ancient disease.

We have not just to look for a single pathogen,

but we have to look for hundreds of them in parallel,

because we don't know what has killed those people,

we don't know if it was one or several pathogens

that were spreading in their population during the time.

And this is just the start of the process.

Even if Johannes manages to isolate DNA

from a disease-causing bacteria or virus,

it could then take months or even years of computer analysis,

comparing millions of genetic sequences,

to identify which specific pathogen was the cause of death.

He's got an incredibly difficult task ahead of him.

But this technology, this science, represents the best chance we have

of finding out what killed the people of the X Tombs.

Back underground, the French team think they're getting closer

to the possible identity of the people.

They've been doing tests on a white powder that was found in the tombs.

It's unusual to find plaster in traditional Roman burials.

'And this plaster contained further clues about how they were buried.'

The presence of plaster and fabric

suggest these bodies may have been bound in an intricate shroud.

This would explain why the shoulders were compressed,

hands resting on their pelvis,

legs stretched out with ankles touching.

And in among the skeletons and plaster,

a second curious substance was discovered.

Amber was a very expensive material.

It was used in burial sites

to ensure safe passage to the afterlife.

But it's rarely been found in this ground-up form,

and never in this quantity.

In all, several kilos were recovered from the tombs.

One final piece in the puzzle was nearly overlooked altogether.

Could the people have been buried dressed in gold-embroidered clothes?

What began as just a mass of bones

is beginning to come into focus a little.

We've got a large number of individuals

who were all carefully laid out,

one by the other.

Mostly adults.

And then there are all these strange finds,

the white powders, the red powders.

And then there's the fine gold thread,

what they thought to be Dominique's hair.

We're getting a clear picture now

of an elaborate and expensive burial ritual

for what seem to be some very wealthy and distinctive people.

In Bordeaux, more clues are coming to light.

One of the French team,

Delphine Henri, has been studying remnants of the fabrics

that were recovered from the tombs.

Delphine believes she can even work out

where the person who made the fabrics came from.

C'est incroyable.

Philippe believes this cultural connection

with the southern Mediterranean can be narrowed further.

While the scientific analyses continue,

there's one remaining historical avenue I want to explore.

The ground directly above the X Tombs was actually a site marked out

for the burials of a very important group of people.

That's the entrance to our tombs over there

and the big structure behind me, that's the Mausoleum of St Helena,

Emperor Constantine's mum. But ignore it entirely for the moment,

because it was built in the early fourth century AD,

way after the time we're interested in.

During that time, end first century to mid-third century AD,

despite what it now looks like, car park, football pitch,

this place was actually a really important cemetery

for the emperor's personal cavalry. Their name changes over time,

but they're perhaps best known as the Equites Singulares Augusti.

"Equites Singulares Augusti"

is Latin for "The Emperor's Chosen Horsemen",

a regiment founded in the first century AD.

They are immortalised in reliefs on one of Rome's greatest landmarks,

Trajan's Column, erected in AD 113.

At the Museum of Roman Civilisation,

copies of the scenes are laid out so we can get a closer look.

The reliefs celebrate Emperor Trajan's epic battles

and ultimate victory over the Dacians, now modern-day Romania,

in the early second century AD.

Our Equites Singulares Augusti

are shown no less than seven times on this column,

and that's more than any other individual battle unit.

Here they are heading off with the Emperor Trajan into battle.

These guys really were the chosen ones

to share in the emperor's most successful military campaign.

This is one of my favourite scenes,

the Equites Singulares Augusti in full battle gear,

the helmets, the shields, the chain-mail jackets,

on their horses, charging in behind their Emperor Trajan,

who offers the horseman's salute, the open right hand.

And they're coming to the rescue of the Roman troops

that are being besieged over here by the Dacians.

It really is the emperor, his crack cavalry, coming to the rescue.

The Equites were the finest imperial horsemen.

Most were foreigners, hand-picked as teenagers from across the Empire.

They were strong and, by many accounts, very handsome warriors.

To be selected was a ticket to great wealth and high status.

They protected successive emperors, both in Rome and abroad,

for over 200 years, from the first to the third century AD.

But in AD 312, the cosy relationship between the Equites and the emperor

came to an end.

The Western Empire was divided by civil war between two emperors,

Maxentius and Constantine.

Maxentius held Rome.

But Constantine marched from the North to oust his rival.

In a final showdown, the two sides faced each other

at the Milvian Bridge, the entry point to Rome

across the River Tiber.

The Equites horsemen sided with Maxentius.

But Constantine was victorious.

Constantine even destroyed the Equites' cemetery.

All that remains are fragments of tombstones.

Many now adorn the walls

of the entrance to the Catacomb of St Marcellinus and St Peter.

The X Tombs were in use around the same time and in the same location

as the former site of the Equites' cemetery,

which raises an intriguing possibility.

The dates of our X Tomb bodies overlap with those of the Equites.

It's unlikely that a space reserved for elites, as the Equites were,

would have been used for burials

of anyone completely unconnected with them.

The people in the X Tombs were mostly young adults,

a mixture of men and women.

Now, we know from surviving tombstones

that the Equites were often buried with their wives and slaves.

The Equites numbered 5,000 strong.

They were foreigners, selected from various occupied territories

across central Europe and also from southern Spain and North Africa.

We've got connections in the funerary ritual

to the southern Mediterranean, to North Africa,

particularly to Tunisia and Algeria.

The complex, elaborate and expensive funerary rituals

with which they were buried not only mark them out also as rich,

particularly that amber, but also fairly distinctive.

Written accounts also tell us they were dressed in jackets

embroidered with silver and gold thread.

The Equites were wealthy, well-fed and well connected.

But when overwhelmed by waves of mass death,

it's conceivable that the Equites' community may have converted

pre-existing underground chambers, possibly disused water systems,

into a mass burial site.

It's only a theory, and we may never know for sure,

but from all the evidence we have at the moment,

it certainly seems plausible

that the X Tombs could be the last resting place

for over 2,000 of these great horsemen and their families.

Soldiers chosen to protect the Roman emperor.

What I love about this investigation

is the way it's been able to put not just the flesh back on the bones

but to have turned these skeletons back into real people.

They came here to the Caput Mundi,

the capital of the world,

the kind of Ancient Roman version of the American Dream,

and the irony is that it was also here in Rome

that disease found its perfect breeding ground

and, ultimately, killed them.

Subtitles by Red Bee Media Ltd