4,000-Year-Old Cold Case: The Body in the Bog

This programme contains some violent scenes.

4,000 years ago. The dawn of European civilisation

and the birth of a macabre and brutal ritual.

Today. Hundreds of prehistoric bodies

unearthed from the boglands of Northern Europe.

Their deaths intrigue historians.

Were they all murdered? And why?

Now, a brand-new find could hold the key.

It's another ancient body.

Found preserved in an Irish peat bog.

The skeleton is distorted.

The muscle and skin badly torn.

An international team of experts face a challenge

as they seek to solve an ancient mystery.

The horrific killing of hundreds of our ancestors,

in one of prehistory's darkest eras.

Who were these victims?

And why did they die?

This is 4,000-Year-Old Cold Case:

The Body In The Bog.

A bog in Ireland's midlands.

Where heavy machinery is used to industrially harvest peat -

a fossil fuel used in Irish homes and power stations.

In August 2011, a heavy-equipment operator

spotted something sticking from the bog in front of him.

When he stopped his machinery,

he realised it was the remains of a human body -

flattened and distorted.

One thing was clear - this was NOT a modern corpse.

Since the year 2003, peat-harvesting in Ireland

has uncovered six other bog bodies like this one.

Bringing the total number of Irish finds to over 100.

These mysterious corpses have captured the imagination

of the Irish public, fascinating young and old alike.

And today peat workers are trained to recognise them -

and follow carefully developed protocol.

So, immediately a call went out to archaeologists

at the National Museum of Ireland.

Within days, their excavations had revealed the body of a man.

What secrets will his corpse reveal?

The body is brought to a lab

at the National Museum in Dublin for forensic investigation.

Leading the team of archaeologists and scientists is Ned Kelly.

He's spent a lifetime studying

ancient Irish history and archaeology,

and has investigated the other Irish bog bodies.

They're part of an ancient legacy -

the 300 preserved corpses

found in boglands across north-west Europe.

To historians, these finds offer the chance

to look our prehistoric ancestors in the face.

Forensic science offers experts clues

to diet, lifestyle, and social status

and shines precious light on a dark era for which there are few records.

This is a very, very, very important find.

And it's a big responsibility to make sure

that we get the maximum information from this body.

We owe it to the man lying on the table, to tell his story for him.

Ned Kelly has named him Cashel Man -

after the townland where the body was found.

Now, he and the team must solve the mystery of Cashel Man -

and explain why he died.

Their first task is to decipher

the confusing mass of bone and soft tissue.

The body was in a very unusual position

and it took a while to work out what was what.

The head is missing - destroyed by the peat harvester.

The body is compressed and misshapen by millennia in the bog.

And badly damaged by the heavy harvesting machinery

when it was discovered.

-That looks like the front face of the vertebrae.

-It does.

Despite the mangled condition, it could contain

a wealth of clues about Irish prehistory

that could also explain the mystery

of the entire European bog body tradition,

IF the team can decipher the evidence.

The first questions to answer are -

how did this person end up in the bog?

And what was the cause of death?

Investigations into previous bog bodies revealed they were murdered.

Could this also be true of Cashel Man?

State Pathologist Professor Marie Cassidy

is joining the team to find out.

There's a good bit of tissue. There's an organ there.

It's either lung or heart.

That definitely has to be lung.

There's all the ribs there,

and that looks as if that could well be the heart.

That's the heart. Brilliant.

Professor Cassidy is on her way

to investigate the scene where Cashel Man was found.

She's more used to solving modern homicides.

But the intensity of industrial peat-harvesting in Ireland

means bog-body finds are a phenomenon

Professor Cassidy has become familiar with.

All of the bog bodies that we've had

have turned out to be ancient remains.

The typical features would be the peaty discolouration of the skin.

You can't miss that. Very often, they're squashed or compacted

because of the weight of the peat they're under.

You don't see that with modern bodies.

Even though the body is likely to be ancient,

Professor Cassidy treats this like a modern investigation.

As forensic pathologists,

our training is to go one step at a time, really.

You start off with the body being found,

what information is available.

Her first step is to speak to the person who found the body,

Jason Phelan, a milling machine operator who works on Cashel Bog.

I turn at the right time

and look on the left-hand side, and I saw this piece,

and it was probably maybe six inches triangular.

And was it sticking up above the surface then?

It was penetrating maybe this high, just above the surface

in a triangular shape.

I got out and I checked it, and I went over, and caught it like this,

gently, and gave it a bit of a tug, and when I gave it a tug,

two legs came up, gently out of the bog, which were crossed.

Professor Cassidy also examines the peat-milling machine.

Its sharp spinning blades were responsible

for tearing into the body's chest.

What it means is that there is a tearing motion.

And that would account for the damage that you see

on the body as it was photographed at the scene.

Because the surface skin had gone,

and you are now looking into the guts, if you like, of the body.

Professor Cassidy's investigations will help her assess which injuries

were caused by a 21st-century milling machine,

and which could have been caused in a prehistoric attack.

Next, the team subject Cashel Man's remains to a CT scan.

It reveals details of the bone and soft tissue

and sheds light on who this man really was.

So, you've got humerus, radius, ulna...

This is a young person's spine.

How young do you think?

-Probably 20-25.

-Yeah...

The images from the CT scan allow the team to identify

the orientation of Cashel Man's skeleton.

He is lying on his right side.

His legs are drawn up to his chest

and his hands clasped around them.

But his head and left arm are missing,

destroyed by the peat harvester.

The CT scan also reveals a further detail.

Cashel Man's right arm has been cleanly broken.

For Marie Cassidy,

it's the first clue to the cause of Cashel Man's death.

There's good evidence that this person was injured,

at and around the time of death.

So, we've got an injury with the one arm remaining

that we can identify and we can see the bones very clearly.

This bone here, the bone that runs down towards your little finger,

that's about midway... It's just been literally halved in two.

And that shows an indication of a direct blow.

What we would call probably a defensive injury.

So, he's maybe been fighting with somebody,

whatever weapon they'd been using, he's put up his arm to block a blow,

and the impact's got him on the outer side of his arm

and caused this fracture.

So, that indicates major trauma.

So, amazing! We can actually even...

We're starting to recreate an incident

that he could have been involved in.

The CT scan also revealed two dramatic fractures

to Cashel Man's spine

where the vertebrae have been left severely out of alignment.

-You can see, there, where the cord would be...

-Hmm.

-..compromised there?

-This is so bad.

I'm just thinking in terms of trauma...

The vertebrae appear to have been torn out of alignment.

Is this a clue to a frenzied beating,

a horrific murder or something else?

At the National Museum, the team disagree.

Ned Kelly is open to the idea of a violent attack.

But Deputy Pathologist Dr Michael Curtis is not convinced.

Is that the kind of thing that would result

from being hit on the spine with a pickaxe handle,

or from somebody jumping up and down on the small of your back?

-They don't look to be fractured to me.

-No, they're just mal-aligned.

Mal-aligned, disarticulated, but they do not appear to be fractured.

I don't like that for a blow with an implement.

-No.

-Right.

-It doesn't look as if it's...a blow.

So, that would have been more localised?

Yeah, and you'd probably have a fracture as well.

This is more dislocation.

If Cashel Man's spine was not broken when he died, then what killed him?

While the forensics team continues to scour the body for clues,

Ned Kelly turns his attention to his area of expertise -

Ireland's unique literary record.

It offers a key to the past that's found nowhere else in Europe.

Unlike other countries in Europe where bog bodies are found,

in Ireland we have a relatively huge volume

of very early literary and annalistic material -

mythological material -

that we can trawl through to see if it provides any information

on the context of these bodies.

As in most of prehistoric Europe,

Ireland's ancient history was not written down.

Instead, it was passed from generation to generation

via the spoken word.

But, uniquely, Ireland's oral history was finally recorded

in a series of annals written by early Christian monks

working between 1000 and 1600 AD.

This is real history, this isn't speculation.

It's a very good starting point to look back

on what may have preceded it.

Ned Kelly is hoping these sources will shed light

on the mystery of Cashel Man.

Could he also belong to the grim roll call

of men, women and children brutally murdered, then buried in the bog?

300 such bodies have been found across north-west Europe.

They date mainly from 500 BC to 200 AD - Europe's Iron Age.

Professor Miranda Green is an expert in the culture of this period -

and its bog-body legacy.

The thing which links them altogether is their bog deaths.

But they were killed in different ways.

Some by trauma, some by garrotting, some by drowning.

They have suffered extreme violence.

These are adult people,

one woman and one man from Borremose in Denmark.

The woman, particularly, had had a very savage end.

She had been scalped, and her face taken off.

And the man had been hit hard on the head

and then garrotted with a rope

that is still visible around the neck here.

This is the body of a young girl

from Yde in the northern Netherlands,

she was put in the bog at the age of 12.

Her hair was cut off and placed by her side.

And then she was garrotted.

So, this is the fate of this poor girl.

The evidence is really quite special.

We can see stomach contents,

we know what people ate just before they were killed.

We know how they met their deaths.

We've even got looks of terror on people's faces.

So, you've really got a freeze-framing of people

who clamour for our attention as individuals.

Over 2,000 years later,

the reasons for these deaths are a mystery.

But one thing common to all of the bodies is the bog.

Dr Ben Gearey is a wetland archaeologist.

He studies the history and formation of bogs.

Bogs are incredible places. They have enormously long history.

They have been part of the landscape for millennia.

Bogs are made up of dead plants.

But their unique chemical composition,

which is highly acidic, kills the bacteria that cause decomposition.

Meaning that organic matter is preserved, in a form known as peat.

By cutting into the bog,

Dr Gearey can expose the layers of preserved peat going back millennia.

We've got around 2,500 years of peat accumulation

in this section here. This is sphagnum moss.

And you can see that, for a deposit that is

perhaps 1,000-1,500 years old,

the preservation is remarkable.

Bogs are waterlogged, rainfall is collected and stored in the peat.

This oxygen-poor environment offers ideal conditions

for the preservation of organic matter.

And that essentially equates to the slowing down -

almost, the complete halting -

of the usual processes of biological decay.

As dead matter accumulates, the bog slowly expands -

growing around one millimetre a year. Meaning that, today,

a single metre of peat can contain a record

of 1,000 years of history.

Preserving plant life, ancient artefacts...and bodies.

Within bogs, we essentially have this record,

we have this memory of the past.

The memory of past environments, past peoples and past landscapes.

We just don't have that in any other environment on the Earth.

The unique properties of the bog have preserved

hundreds of bodies across north-western Europe.

In Denmark alone,

around 200 have been dug from the country's boglands.

Pauline Asingh is an archaeologist,

and the curator of Moesgaard Museum,

home to one of the most famous Danish bog bodies.

Grauballe Man was discovered in 1952.

He is around 2,300 years old.

But he's been remarkably preserved by the bog.

You stand face-to-face with a dead man

from a period so far, far away

and he looks like you.

And his nails are very well preserved. His fingertips,

you can still see the small lines in them.

You could see his beard, when he was found.

You could see the pores in his skin... It's fantastic.

Grauballe Man's preserved remains clearly reveal

that he too was viciously murdered.

He had a deep cut from one ear to another.

SHING!

It's a savage wound.

But there's more -

a broken leg, and a fractured skull.

More injuries than were necessary to kill him.

It leaves historians asking, "Why?"

Silkeborg. Less than 30 miles

from where Grauballe Man was discovered

and where the museum holds another famous body.

In 1950, peat cutters working on a bog outside the town

unearthed Tollund Man.

He, too, lived around 2,300 years ago.

He, too, was murdered.

During excavation, it became very clear,

very, very quickly, that he was hanged,

because he still had a noose around his neck

very, very, very tightly.

And you can also see the furrows, here, groove around the neck,

at a very high position that indicates that he was hanged.

Tollund Man's head has been remarkably preserved by the bog.

And his extraordinary remains still tantalise archaeologists.

Look, if you see his face, it's so fantastic,

and you see his wrinkles.

You see his stubbled chin

and so it's almost like a CV - but we can't read it!

One thing scientists HAVE been able to read

is the contents of Tollund Man's gut.

It showed he had eaten a porridge of barley and linseed the day he died.

Similar to Grauballe Man, whose stomach was also preserved.

This is some of his last meal, Grauballe Man's last meal.

And it has been eaten more than 2,000 years ago.

They found out there were seeds of 66 different herbs.

It's not the best - it's animal food, or poor man's food.

And it's interesting, because many of the other Danish bog bodies

has the same last meal inside when they found them.

Could Cashel Man's stomach reveal HIS final meal?

The team in Ireland first need to locate the stomach.

But identifying it in the jumble of soft tissue is not easy.

They start by trying to locate his oesophagus.

If he's got a trachea, behind it

would be maybe his oesophagus behind it.

In which case, you've got a portal of entry to his GI tract.

You could core out a bit, like a little core biopsy or something.

The only trouble is you're going down

into what you can't see underneath.

Yeah, but it would be minimally invasive.

Oh, yeah, but in some respects,

it's probably better to treat this

as an archaeological excavation almost.

Professor Cassidy decides the safest way to look for the stomach

is with a fingertip search of Cashel Man's internal organs.

But her efforts are in vain.

She finds the stomach has entirely decomposed.

-The stomach...

-The stomach's going to be in this area here.

So, the stomach is all gone?

There's just nothing there, this is all very ratty looking.

It's a disappointment.

Without the stomach, the team will never know Cashel Man's last meal.

But carbon dating has revealed when he died.

And the results are a shock to everyone on the team.

The body is over 4,000 years old -

1,500 years older than the team expected.

For Ned Kelly, it's a remarkable discovery.

This body goes back to the early Bronze Age.

It's much earlier than we anticipated.

That's very, very exciting.

It's probably the earliest fleshed bog body.

Cashel Man walked these bogs in Ireland

centuries before Tutankhamen lived in Egypt,

making this the oldest fleshed bog body

not just in Europe, but the world.

It shows the bog-body tradition stretches right back

into our darkest prehistory.

But it's not just the body that holds the clues

to Cashel Man's story. At the bog where the body was found,

the layers of peat COULD also conceal ancient evidence.

Archaeologist Dr Ellen O'Carroll has come here to look for it.

She's taking a peat core sample

and hoping the record of vegetation preserved within it

will offer an insight into Cashel Man's world.

This is our peat core.

50 centimetres of peat

which represents about 700 years of environmental history.

At the bottom of this core, we have evidence of a marginal forest

where alder trees were growing.

You can see the wood remains in here,

and you can see the reeds just poking out here.

As you get up further, you can see eriophorum or bog cotton,

which is the white cotton you see growing on the bogs.

What you can't see with the naked eye,

and what I analyse back in the lab as well, is pollen.

You can fit 30 pollen grains on the top of a pin,

and so they're so tiny you need the microscope to identify them.

Dr O'Carroll hopes her analysis of the pollen grains

will reveal what vegetation was most prominent

around the time of Cashel Man's death.

Now, that looks like ranunculus, I think...

..which is a buttercup.

It's kind of got a globular grain surface.

There's a hazel pollen grain.

The variety of species she detects may indicate

the scale of human activity in the area where Cashel Man was buried.

That looks like a...

an ash pollen grain - Fraxinus.

Ash and birch quickly grow after mature forest has been clear-felled.

Pollen from these two species dominate the samples,

indicating both ash and birch were widespread.

It's a sign of intense human activity

in the area where Cashel Man was buried.

The presence of ash indicates that humans were around the area,

they were cutting down the forest.

Ash is used as an indicator of humans interacting with the woods

and cutting them down. The rise of the ash and the birch curves

and the exploitation of the woodland indicates that Cashel Man died

within the vicinity of a community that was quite vibrant.

Further analysis of the peat core

reveals more evidence of human activity -

microscopic traces of charcoal,

indicating fires were burnt in the area.

Confirmation that Cashel Man was buried close to a busy community.

But what would this community have been like?

Dr Billy MagFhlionn has studied Bronze Age archaeology.

It's allowed him to recreate the technology of this vanished world.

What I try to do is look at the originals

and imagine how they would have been done,

and using similar types of technology

to what they had in the past.

Dr MagFhlionn has recreated an ancient method

of casting objects from bronze.

It shows the skills and scientific knowledge Cashel Man's tribe

would have mastered to produce even an everyday object like an axe.

What we are going to do is take these bits of scrap bronze

and put them in the crucible here and heat up the whole thing.

The idea is that the metal will melt and turn to liquid.

To make a high-quality casting,

the bronze needs to be heated to at least 2,000 degrees.

To achieve this, prehistoric bronze-smiths

figured out an ingenious system of bellows.

You'd be starting the next stroke before the first one is finished.

So, there's a constant flow forward of air.

It looks simple enough, but it needs a little bit of coordination.

Once the bronze is molten, it is poured into a clay mould.

This method of casting gave Cashel Man's people

the ability to mass-produce essential items

like weapons and tools.

It will clean up and polish very nicely

and be able to hammer a sharp edge onto it.

It is industrial production.

What we saw here was the final step in a very long process

where metal has to be produced.

First, you have to prospect for the metal, find the ore,

then you have to mine it,

then extract the metal from the ore in the process of smelting.

But what really comes across is how refined they had their skills.

And, sure, their technology is at a more basic level than ours,

but what they could do with what were, essentially,

more limited conditions than what we have now was astonishing.

But who were these ancient metalworkers,

and what was their civilisation like?

They left no written records.

The accounts we do have come from the Romans

as they expanded their empire across Europe.

The writer Tacitus described tribes living in villages....

..and who...

To the Romans, there was one word for people like these -

"barbarians".

It goes back to a classical term - "barberoi".

Meaning people who, in a sense,

speak in languages which are incomprehensible

to the classical world - "Bar, bar, bar..." -

that's the origin of it.

But, basically, it had come mean "people who are not like us",

people who are different from us in the classical world,

because they're not civilised,

they don't write things down,

they don't have organised laws,

and they don't have organised structures,

and so they're almost not quite human.

But historians now believe these Roman accounts are highly subjective

and don't reveal the true nature of Iron Age Europe.

You have to look at the Romans as the imperialists that they were.

And the Roman world-view

was of course that the Roman way of doing things was THE best way.

And, indeed, the only worthwhile way of doing business.

Nearly two centuries of archaeology has revealed

the truth about a complex European society -

the Gauls, the Celts, the Germanii and the Goths.

These were confederations of hundreds of diverse tribes,

organised to protect their interests from the advance of Rome.

The knowledge we have

is of an immensely sophisticated group of people.

We know of hierarchies of people...

political leaders, religious leaders and other people.

So, in fact, a highly stratified society.

But one without writing, so it's largely silent

and very difficult to get at.

There would have been trading centres

where you would have had something approaching an urban economy.

So, the idea of international trade,

and commerce and exchange, were not foreign concepts.

But the backbone of the economy was probably agricultural production.

To these farming people, the land was sacred.

And studies of ancient European iconography shows that -

as with the Greeks and Romans -

fertility deities were central to their belief systems.

And may be the key to explaining the bog-body phenomenon.

Derryville, just 15 miles from Cashel Bog.

A huge excavation is revealing prehistoric craftsmanship

on a massive scale that may also unlock

the ritual beliefs of the Iron Age.

Archaeologists have uncovered a network of finely crafted trackways.

They hint at the belief systems central to Cashel Man's culture.

Dr Henry Chapman is an expert in interpreting wetland archaeology.

Now, this one is beautiful.

It's a wickerwork hurdle,

so you can see it extending quite some way along here.

Some Iron Age trackways in Europe may have been used

as roads for taking cattle safely over bogland.

But not all of them.

At Derryville in Ireland,

none of the trackways that have been found actually cross the entire bog.

Instead, each ends right in the centre,

where the topography indicates the marsh was at its wettest.

Why? One clue could be the wealth of valuable objects

found buried in boglands.

The scale and locations of these hordes lead historians to believe

they're not buried treasure, but votive offerings to ancient deities.

A votive offering is simply a gift

that is presented by people

to a god or a goddess

in return for some expected favour.

It's an offering which has been made on behalf of the community.

One such offering excavated from an Irish bog

was a large pail of Iron Age butter,

a valuable commodity 2,000 years ago.

Ned Kelly believes it was an offering to the goddess of fertility.

There was far too much of this butter

for it to have been simply buried and overlooked.

We're clearly dealing with material

that has been deposited for a reason.

That reason, I believe, was the protection of the cattle herds

and to ensure continued supply of milk by the herds

and proper food resources.

It may sound extraordinary, but the evidence to support this theory

can be found within living memory in modern Ireland.

We know that butter continued to be deposited in a votive manner

up into the middle of the 20th century at least.

And we can trace that tradition back

through the deposits in the bogs and in the lakes of Ireland.

Other ancient artefacts associated with fertility

have been excavated from Irish bogs.

Cauldrons, feasting cups,

millstones for grinding grain...

and these are also thought to be offerings to the goddess.

Sacrifices like these hint at the sacred nature

of the boglands of Iron Age Europe.

And, to Dr Chapman, this evidence shows

the trackways at Derryville were not about economics, but ritual.

If it doesn't make sense in any practical sort of world,

then it's likely to be something which is...

a different sort of practical, something about belief systems.

It's allowing them to ask for things, to ask for help,

or to ask for thanks.

Those events which happen, either at times of conflict

or at times when they require a good harvest.

It's those sorts of events

which are what these things are probably about.

Trackways may have allowed Cashel Man and his tribe

to access the bogs to commune with their deities.

But why deposit a body in the peat?

Archaeology has shown that, typically,

these people did not bury their dead.

Normal people were burned,

cremated, and put in an urn or a pot

or just a shallow pit.

So, this is highly unusual.

Could the bog bodies THEMSELVES have been offerings?

Were these men, women and children deliberately murdered,

then buried in the bog to appease the gods?

The way that he was put to rest in the bog,

lying in a sleeping position on the one side,

somebody must have closed his eyes and his mouth,

because you don't look this peaceful if you just hanged!

I personally think that he was sacrificed to a god or goddess.

Could our ancestors have practised ritual murder?

Pauline Asingh has studied Grauballe Man's diet,

his injuries and the local archaeology.

She has used this evidence to piece together his final moments.

It's led her to believe Grauballe Man died

as part of a sacrificial execution -

a ritual in which the whole community was involved.

Then they walk through the old fields...

..and then we reach the bog.

Then, somebody hits him on his left shin bone.

And then he fell on knee.

And when he was laying on his knees,

somebody cut him from ear to ear...

very deep.

And the blood will flow from his neck here to the bottom.

So, they give a life from this world -

from our world - to the underworld.

Could the bog bodies really be evidence

of the widespread practice of ritual murder?

Could Cashel Man also have been sacrificed?

Ned Kelly believes clues to this theory might be found

on one of Europe's most precious prehistoric artefacts -

the Gundestrup cauldron.

This is a rather elaborate cauldron made of silver

which was found in a bog at Gundestrup in Denmark.

It dates to 200 BC, the same period as many of the bog bodies.

The cauldron is decorated with panels depicting Iron Age deities.

One image shows a ritual being performed

in honour of the goddess of fertility.

There is a figure who is holding a victim over a cauldron.

This victim is either being drowned in the cauldron,

or perhaps, he has had his throat cut,

it's an image of ritual killing.

And there are other images relating to ritual killing on this object.

We have one image of a male deity holding aloft two human victims,

who, in turn, are holding aloft two pigs who are also to be sacrificed.

And on an image before me here,

which shows the goddess,

lying at her breast are a human victim

and a pig who have been sacrificed.

There are a number of references on this object to human sacrifice.

For Ned Kelly, the Gundestrup cauldron

offers an eyewitness account of human sacrifice

straight from the Iron Age.

And, for him, this crucial evidence

helps explain the mystery of the bog-body murders.

This cauldron shows the context within which those killings

may have taken place in Ancient Ireland.

Was Cashel Man ritually killed by his own people,

as a sacrifice to the goddess of fertility?

His extensive injuries may offer further evidence to support the idea

and the macabre practice known to historians as "overkill".

Very often that sacrifice is done

with far more violence than is necessary actually to kill,

as though the act itself

conveys sacredness.

The more violent, the more complex the killing,

in a way, the more valuable the gift is.

It's far more than just sending somebody over to the next world.

It is highly ritualised.

It's spectacle, it's theatre,

it's a collective act involving collective responsibility.

The conservation lab at the National Museum of Ireland.

The forensics team is considering whether Cashel Man's injuries

could be evidence of a ritual overkill.

But there's still disagreement.

Deputy State Pathologist Dr Michael Curtis believes a weapon,

such as an axe, could NOT have been responsible.

Well, I find it hard to believe

that it's displaced the vertebrae without fracturing them.

If it's impacted them enough...

I mean, it has to be the sharp edge.

If the sharp edge has gone in sufficiently

to displace the vertebrae, why are they not fractured?

This trauma to the spine may not, in fact, be an injury at all.

The theory of overkill was developed

following the Danish bog-body discoveries in the 1950s.

But modern research by forensic anthropologist Dr Niels Lynnerup

is rewriting that theory.

He's joining the team in Ireland

and doesn't believe the injuries to Cashel Man's spine

were caused by a weapon at the time of death.

If that was an injury that was physically induced,

what sort of damage would you expect to see on those vertebrae?

There is no sign of trauma,

in terms of fracturing of the vertebral bodies,

-of fracturing of the posterior, aspects of that.

-OK.

-I cannot recall seeing...

-It's a massive trauma.

-Yeah.

That's road-traffic accidents - falls from a height.

Even for instance by kicking somebody in the back wouldn't...

No, never, never.

Dr Lynnerup has an entirely different explanation

for the rupture to Cashel Man's spine - bog trauma.

It all starts with the chemical composition of the bog.

There are some substances in the bog

which actually helps preserving the bog body.

At the same time, there are other substances, acidic substances,

which start degrading some of the tissues. For instance, the bones.

The acidity can be so strong

that the bones can become completely bendable.

They get, basically, like wet cardboard.

Dr Lynnerup's explanation is that the powerful acids in the bog

where Cashel Man was found softened the ligaments

holding his spine together.

And that this effect was intensified

by the increasing pressure on the body, as the bog grew above it.

The bog is undergoing a continuous development.

It may actually grow in height, at some point in time,

it might even sink a bit.

You get this active environment

and this environment can directly, or indirectly,

put a pressure on the bog body.

Dr Lynnerup believes the weight of the bog is responsible

for pushing the softened vertebrae in Cashel Man's spine

out of alignment over thousands of years.

We've seen something like that in Danish bog bodies.

It's because when the ligaments degrade a bit,

or get a bit more soft, then they can start,

depending on how the body is lying, to come out of alignment.

To me, it seems postmortem.

Dr Lynnerup questions whether overkill was a real phenomenon.

But Ned Kelly has led cutting-edge forensic investigations

into two other mutilated bog bodies.

And believes they offer compelling evidence to suggest that,

in Ireland, overkill really did take place.

The first was the body known as Clonycavan Man.

A blow in the face broke his nose

and he was then set upon around the head with an axe.

This is Old Croghan Man.

Modern forensics revealed that he was the victim of a gruesome murder.

He died as a result of a stab wound to his heart...

..probably with an Iron Age sword.

WET, METALLIC SQUELCH

He was decapitated and cut in half.

The other parts of the body disposed of elsewhere.

There's far more done to this body

than needed to be done to kill the man.

Ned believes the extensive injuries to these bodies

are evidence of overkill.

And that science backs him up.

I would have to conclude, based on the evidence

that I've been presented with

by the pathologists in relation to the Irish bog bodies,

is that these are bodies that have multiple injuries.

So, we have to interpret that.

Now, whether you call it "overkill",

or what you call it, it's just a matter of semantics.

Further evidence on Cashel Man's body

may show he, too, suffered a violent death.

The first clue is a long thin cut to his back.

That was revealed by excavation.

It was down in the peat, so I don't see how that particular cut

could possibly have been caused by the milling machine.

Oh, I agree, I agree. It's remote from it.

If it's definitely not the milling machine, then it's something else.

The thin cut suggests a slash with a very sharp blade.

Meanwhile, the clean break to the arm is a definite defensive injury -

typical of someone deflecting a blow.

For Marie Cassidy, the evidence suggests

Cashel Man's death was violent.

-Your injury to your arm looks like a true injury.

-Yeah.

And if that's a true injury,

then you have to think of a mechanism.

The most likely mechanism, in those days,

is you're in the middle of a fight with somebody wielding something.

And, therefore, it's quite likely that the death is trauma.

Forensic science has at last confirmed

that Cashel Man was murdered.

And it can also reveal how these men lived.

Dr Andrew Wilson analysed hair samples

taken from the bodies of Clonycavan Man and Old Croghan Man.

Hair is quite a unique resource.

It locks both physical information

and biochemical information.

We can tell something about the chemical information

that perhaps tell us about that person's diet.

By studying samples of hair,

Dr Wilson is able to unlock

the dietary record hidden within the structure of each strand.

With hair, you've got that incremental growth,

roughly a centimetre each month.

And if you've got long enough hair surviving

therefore you can build a complete timeline

of the final months of the individual's life.

Tests revealed both Clonycavan Man

and Old Croghan Man enjoyed a diet rich in protein.

This indicates both men may have been of high status.

Cashel Man's head was destroyed by machinery.

But the team did find his scalp,

flung several yards away by the peat harvester.

We've got samples from Cashel Man's scalp,

roughly 18 to 20 millimetres in length,

which, in itself, is representing roughly two months' hair growth.

Dr Wilson places these prehistoric hair samples

into a scanning electron microscope.

The intense magnification reveals the structure of the hair,

while isotope analysis deciphers the unique chemical signatures

left in Cashel Man's hair by his diet.

Those signatures tell us that we're dealing with an individual

who had most of the food groups,

dietary proteins in the form of meat and dairy, as well as cereals.

That's not dissimilar to the bog bodies that we've looked at before -

Old Croghan Man, Clonycavan Man.

The evidence of a protein-rich diet

suggests Cashel Man may have been of high social status,

like the two other Irish bog bodies.

So, who were they?

Ned Kelly is at the National Library of Ireland,

where he's searching through

some of the country's oldest literary records.

And he's found a clue.

The Annals of the Four Masters

was compiled by Christian scribes in the 1600s.

But it records oral accounts of Irish history

dating from as early as 2200 BC.

One such account describes the excessive violence used

to murder an ancient Irish king.

OK, you have a reference here

to the death of the High King of Ireland, Murchadeach MacAirch.

According to the Annals, the king was...

The king is killed in a number of ways. He's drowned.

He's burned.

And, in other references, he's stabbed as well.

This is referred to as the "triple killing of kings".

References to the triple killing of kings

occur throughout Irish folklore.

Could such a killing explain the extensive injuries

to the Irish bog bodies - and show they were kings?

If so, evidence from further annals may explain why they died.

An account of an inauguration ceremony describes how the new king

was symbolically wedded to the land over which he was to rule -

in this case, the western province of Connacht.

"And when Fedlimid mac Aeda meic Eogain had married

"the Province of Connacht" - married the Province of Connacht -

"..in the manner remembered by the old men

"and recorded in the old books;

"and this was the most splendid kingship-marriage

"ever celebrated in Connacht down to that day."

This symbolic marriage of the king to the land itself

made him directly responsible for the success of the harvest.

And came with potentially fatal consequences.

If it fails, he will be held accountable

for failing to keep the goddess in a benevolent frame of mind.

And he will be replaced through his ritual killing.

WET, METALLIC SQUELCH

Could these fragments of history show Cashel Man was a murdered king?

Evidence from the body of Old Croghan Man supports the idea

and suggests to Ned this man was certainly of high status.

His hands have been perfectly preserved.

He has no calluses on his hands.

This is a man who did not engage in any manual labour.

He had an armlet.

I believe that armlet signifies he was a person of rank.

While Ned searches the literary record

for clues to explain Cashel Man,

science may be on the verge of a bold new theory

to explain all 300 bog bodies -

and reveal the powerful, larger force

that spread across Iron Age Europe.

The Derryville dig. Just 30 miles from where Cashel Man was found.

And where ancient trackways led prehistoric tribes

to the wet heart of the bog to practise their darkest rituals.

Scientists working here have long known

that rainfall feeds the bogs, causing them to grow.

Now they're asking, could rainfall also be the key to ritual murder?

The peat has preserved not just human remains,

but also microscopic fossilised amoebae.

And scientists believe these could throw light on the bog body murders.

They're known as testate amoebae.

Testates live on the bog surface.

We know from modern studies of testate amoebae

what moisture preferences different species have.

We can use knowledge of the present as a key to the past.

Modern science has revealed

which testate species flourish when it's wet,

and which ones thrive in dry conditions.

Environmental archaeologists like Dr Ben Gearey now believe

this fact could open the door

to thousands of years of climate history.

By analysing samples of peat, he is able to extract fossilised testates

that lived thousands of years ago.

As bogs grow and change over time

depending on how wet or dry they are, of course,

this will be reflected by the composition

of the communities of testates that are living in the peat.

Under the microscope,

Dr Gearey is able to identify the different types of testate amoebae.

This is another species of testate.

It's called Arcella discoides.

This is an indicator of generally rather wet conditions.

This is Hyalosphenia subflava.

This is an indicator of a comparatively dry conditions.

By analysing peat samples, Dr Gearey is hoping to identify

which species of testate - wet or dry - are most dominant.

This work could reveal the weather patterns faced by ancient tribes

thousands of years ago.

And offer an insight into the challenges posed by climate

to these prehistoric farming communities.

Meanwhile, at the National Library,

Ned Kelly has found another clue to help him explain Cashel Man's death.

It's a medieval map.

Like the annals,

it records information from thousands of years earlier.

In this case, the boundaries

of Ireland's ancient kingdoms,

and the inauguration hills on which tribal kings were crowned.

The map shows Cashel Man and Old Croghan Man

were buried in bogs at the foot of inauguration hills.

Ned believes this is a sign both men were deposed kings -

each buried in the shadow of the hilltop

on which they had once been crowned.

To find out more, he's exploring the hill

overlooking where Cashel Man was found.

There's a wonderful view back here across the bog...

..Cashel bog.

That's the bog there in the middle of which Cashel Man is.

The map shows that the hill and the bog mark the boundary

of an ancient tribal kingdom,

part of modern-day County Laois.

We're just here -

Crook Locha, I think.

And the bog is over here, on this boundary.

You can see there's a boundary running around here.

The hill's wide, flat summit overlooking the kingdom

made it a place of assembly for ancient tribes

performing kingship ceremonies.

Ned believes they came here to crown their kings

AND to decommission them in murderous rituals.

What I'm proposing is that the bog body down here in Cashel Bog

is also associated with kingship ritual.

He, in my view, is a king

who was probably inaugurated here on this hilltop.

And when his kingship failed

he was ritually killed, and he's buried down there

in the boundary surrounding this inauguration hill.

It just cannot be coincidental.

Ned's theory is that Cashel Man

was a Bronze Age king

faced with a failing harvest,

murdered by his tribe

and sacrificed to appease the goddess of fertility.

This theory could at last explain

the mystery of the prehistoric bodies buried in Irish bogs.

But not those from the rest of Europe.

It may for places like Ireland

where you have this early medieval evidence.

But it doesn't work for the majority of bog bodies found

for example in Schleswig-Holstein in Denmark,

and in the Netherlands and elsewhere in Britain.

In Europe, archaeologists have found the bodies of men and women,

boys and girls. Clearly, these can't all have been kings.

Could a common theory ever explain them all?

Experts have scrutinised archaeology,

ancient history and the bodies.

Now the bog itself may provide an answer

and reveal the powerful force that grew the boglands,

but rained chaos on ancient Europe.

Dr Ben Gearey has spent years

studying how bogs are formed and fed by rainfall.

And how the record of this rainfall is preserved

in the form of microscopic fossilised testate amoebae.

If we are identifying a relatively large amount

of the discoides in that sample,

that indicates that that is a relatively wet environment

represented by that sample.

If we're seeing a greater proportion of the dry indicators,

that shows the opposite. It shows a relatively dry surface.

For 20 years, scientists have been collecting data

from sites like Derryville.

Their goal - to use testate amoebae to track changes

in the wetness of these boglands

and reveal prehistory's changing climate.

There's been a huge amount of work done on different bogs,

different sites, in Ireland and indeed in north-west Europe,

attempting to track changes in bog-surface wetness over time,

and then to relate that to climatic shifts, really over the last

5,000 years or so, or maybe even longer.

This work is unlocking the climate record

preserved in Europe's boglands.

And the data has revealed an insight

into the dramatic changes in climate faced

by prehistoric tribes thousands of years ago.

We tend to see that there is increasing evidence

for a climatic shift,

a shift probably to a wetter and colder environment

around about the Bronze Age-Iron Age transition.

Very broadly, around the time that we do get increasing evidence

of bog bodies appearing in wetlands.

This research reveals a dramatic fluctuation

in Europe's climate around 750 BC -

when rainfall increased and temperatures dropped.

It lasted hundreds of years.

Probably the most significant climatic event since the Ice Age.

Could this evidence of a climate shift to a wetter colder Europe

explain the bog bodies?

If you imagine, in prehistory,

when people don't have the advantage of satellite-based information,

those sorts of things, they don't have that record.

So, when things change,

and they continue to get wetter and colder, they don't know why.

But it's affecting their economics.

European Iron Age tribes were dependent on farming.

For a society like this,

a colder climate with more rain could have meant disaster.

Destroying their harvests

and leaving them facing starvation.

Those things are where people have to respond in some way.

And the way you respond to that, when you feel impotent,

you have to do something, that's when belief systems

and ritual activities probably take place.

Did The Iron Age tribes see their harvests devastated

by climate chaos and interpret that as the work of angry deities?

And was their solution to march living sacrifices

into the soaking bogs of Europe

to murder them and appease their gods?

In terms of ceremonial prehistoric ones

that we think are ritual killings,

um, those ones... it's entirely possible

that they are related to changes in the environment,

people responding to the things which they can't control.

Could this controversial theory answer prehistory's darkest mystery

and explain the bog-body phenomenon across Europe?

We know it was the rain that grew the bogs.

But did the rain also drive our ancestors to commit murder,

in order to ensure their own survival?

Thousands of years later, are these bodies their unfortunate victims?

All murdered.

All sacrificed.

All buried in the bog.

Subtitles by Red Bee Media Ltd