20x03 - The End of the Romans

[bunniefuu]

♪♪

-The Roman Empire stretched
from Hadrian's Wall in Britain

east to Babylonia,
in present-day Iraq,

and across
the northern coast of Africa.

Expanding and contracting,

the empire
lasted nearly 1,000 years,

influencing politics, art,

and architecture
for millennia to come.

Historians and archaeologists
have long theorized

about what caused the collapse
of such a powerful civilization.

Did surrounding enemies
become more ruthless

while Roman emperors
lost their ability to lead

or was it something far beyond
the control of any emperor

or military leader?

Today, archaeologists
and scientists speculate

that a series
of virulent pandemics

took their toll
on the mighty realm.

New scientific advances have
allowed researchers

to identify
the pathogens responsible

for decimating
Ancient Rome's population.

Did mass disease
weaken the military

and allow adversaries their
first victories?

Or were other forces involved?

Centuries of climate data
from all over Europe and Russia

has shown how
the climate changed

across the empire.

How would a sudden temperature
drop have affected

the health
of Rome's inhabitants?

Cooling temperatures
likely provoked

the great westward migrations

that changed
the history of Europe

and brought Rome into conflict
with numerous groups.

And then, at a moment
when it seemed the empire

might return
to its former glory,

the emperor's troops failed
to reconquer lost territories.

Could a violent natural disaster
be the real reason Rome fell?

What destroyed one of the most
powerful civilizations

in history?

♪♪

♪♪

-The decline of Rome begins
several centuries

before the empire
actually falls.

In the year 165 A.D., two men
lead the vast dominion --

Marcus Aurelius
and Lucius Verus.

That year,
Marcus stayed in Rome,

while Lucius left to fight
the Parthian Empire in the East.

Rome is victorious
over the Parthians,

but in the coming years,
many in the empire wonder

whether an excess of violence
brought disfavor from the gods.

Rome takes control of the
Parthian capital city, Seleucia,

which is located
on the Tigris River

and is home to an important
temple to Apollo.

Initially, Roman troops
enter the city peacefully,

but then looting begins.

-So, it was the year 165,
after four years of w*r

between Romans and Parthians,
in the disputed Middle East.

The victories achieved
by the Romans

gave them access to Mesopotamia,

and they were able to sail
in several columns

down the Euphrates
and Tigris rivers,

to the heart of Babylonia,
where the large capitals

of the Parthian Empire
were located.

The largest one was
Seleucia-on-Tigris,

a huge city with hundreds
of thousands of inhabitants,

the equivalent
of Rome or Alexandria

from the Parthians'
point of view.

Although it was
a cosmopolitan city,

its history was mainly Greek.

It was like a Greek city.

♪♪

The city gates had been opened,

and the Romans were able
to enter peacefully.

But fairly quickly,
things got out of hand.

The city was pillaged
and set fire to.

A m*ssacre took place,

and the Romans left with
all the riches they could find.

What happened was that
the city's high temple,

dedicated to Apollo,

"Long-haired Apollo,"
as he was known at the time,

was where
the plundering took place.

And everything considered
valuable or prestigious

was taken,

notably the
huge statue of Apollo,

which ended up back in Rome.

And so all the Romans
were able to see it

at the end of the w*r
when victory had been declared.

Long-haired Apollo
was the god of plagues,

the god of healing and medicine,
and also the god of archery,

who sent death and disease.

And so, without doubt,

the Romans associated
this statue

with the shameful plundering

and pillaging
of the city of Seleucia

and with the sort of
divine retribution

which befell them afterwards,
the epidemic which hit Rome

at more or less the same time
as the triumphal victory.

♪♪

-Lucius Verus and his army
return to Rome victorious in 167

but have unknowingly
brought back with them

a dangerous enemy.

The size of the Roman Empire
reaches its historic peak.

Estimates put its population

between 50 million
and 90 million people,

roughly 20% of the
world's population at the time.

But at this moment of triumph,
the empire is rocked

by an epidemic
of unprecedented strength,

spread by
the returning military.

Is Apollo punishing Rome
for the destruction of Seleucia?

The Antonine Plague
arrives in Rome

in the last years of
the Pax Romana,

when the empire is at the height
of its power, control,

and population.

The first-known major epidemic
to hit the Roman Empire

continues for the next
several decades,

and between 5 million
and 10 million people

lose their lives.

Galen, an early physician famous

for his medical investigations,
recorded the unfolding tragedy.

Véronique Boudon-Millot is
an expert on Galen's writings.

-I spent three more years
in Rome,

and when the great plague
broke out,

I quickly left the city
and hurried back to my country.

To my knowledge, there was no

sufficiently powerful medicine
to fight this plague,

which spread
everywhere before dying out.

Galen left Rome as soon as
the epidemic had been declared

and took refuge, so to speak,
in his native town,

where he spent two years
in relative peace and quiet,

according to what he wrote
at the time.

He went about his usual
daily life.

And then he received a letter
from the joint emperors,

Marcus Aurelius and
Lucius Verus, ordering him --

it was indeed an order --
to join them in Aquileia.

And when he arrived in Aquileia,
he found an army camp

where the soldiers
were crammed in.

The camp was overcrowded,

and no sooner had he arrived
when a terrible epidemic,

stronger than before, broke out
and decimated the soldiers.

The two emperors,

Marcus Aurelius
and Lucius Verus,

were terrified and left --

"ran away,"
in the words of Galen --

and returned to Rome.

And Galen stayed there alone
with a few other army doctors

and had to deal
with thousands of casualties,

he tells us, among the soldiers.

Pestilence was like
a savage beast,

destroying its victims
horribly, devouring them --

not in small numbers,
but whole towns of them.

Most people died not only
because of the plague,

but also because it all took
place in the heart of winter.

Despite his long experience
as a doctor,

having witnessed many things
in his career,

he said that
the extensive pestilence

was something
he'd never seen before,

and he described
unheard-of symptoms.

The theory which is most
prevalent today

is that it was smallpox,

the very first smallpox
epidemic in the Roman world,

with a population
who had no immune system

against a disease
never before encountered.

The devastation
was clearly significant,

but it's still very difficult
to put a figure on it.

-Galen notes the devastation

the disease causes at
the military camp in Aquileia.

The soldiers are stationed there
in preparation for battle

against barbarians
from the north and east.

This fighting would go on
for years,

as a variety of tribes tested
the strength of the Romans

along the
Danube and Rhine rivers.

The ongoing conflict
takes a toll on the empire.

As the pandemic rages, Rome,

desperate to keep their
military fully staffed,

begins recruiting soldiers from
across its vast territories,

a decision
that may have weakened

the cohesion
of the once-mighty army.

Barbarians crossing into Greece,
deep in Roman territory,

defeat these soldiers,

one of the empire's
first losses.

In August 170, enemy forces
attack one of the empire's

most sacred sanctuaries,
the Temple of Eleusis,

a place of pilgrimage

famous throughout
the Roman world.

This stunning act of violence
has repercussions

across Ancient Rome.

-Every year,
hundreds of initiates

came in procession
through this gate.

The initiates were
young, old, men, women,

free citizens, and sl*ves.

The initiation was open
to everybody, on two conditions.

They had to be able
to speak Greek

and not have blood
on their hands.

If these two conditions
of purity were fulfilled,

anyone was entitled to receive
the blessings of the goddesses.

-According to Greek mythology,
Eleusis is where

the goddess Demeter
gave humanity

the gift of agriculture.

A temple was built to honor
the site, and every year,

pilgrims arrived to be part
of secret religious rites,

known as the
Mysteries of Eleusis.

The site's importance
for the empire

and the sacred objects within

make the temple an obvious
target for the barbarians.

-It was an enormous space,

a jumble of 42 columns
54 meters wide,

20 meters
more than the Parthenon.

And in the center of
this huge area,

on the side of which were
the seats for the initiates,

there as a special chamber,
called the Anaktoron.

This was
the heart of the sanctuary.

It's still in
the same place today,

despite all the changes
to the site over the centuries,

and the centerpiece
of the ritual.

It's the area where
the sacred objects

were shown to the initiates.

And it's here that the initiates
discovered something,

which we know very little about,
as they were sworn to secrecy.

So we can only surmise as to
what happened in this spot

and guess at what
the mysteries were.

♪♪

-The Costoboci warriors, a tribe
from the Southern Balkans,

overrun the shrine,
plunder its sanctuary,

and then burn the temple
to the ground.

This attack
on such an important site

signals Rome's
changing fortunes.

♪♪

-This is
Emperor Marcus Aurelius.

It was his armies who couldn't
prevent the Costoboci

getting through

and causing the catastrophic
pillage and destruction.

There's a statue of him

because he was the one
who had everything rebuilt.

♪♪

Between the years 171 and 176,
in the Danube region,

there were five years
of bitter w*r

to keep the barbarians at bay
and bring about peace.

♪♪

From the Greeks' and Romans'
perspective,

it would seem that the situation
had returned to normal

and that the affront of having
been violently plundered

had been forgotten.

But from the barbarians'
point of view,

they saw things differently.

They now knew that they could
break through.

The warlords could now spot
the weaknesses

just across the empire's borders

in the hope of once again
seizing valuable booty

and returning triumphant
to their own people.

-The unimaginable
has happened at Eleusis.

Barbarian tribes in territories
surrounding the empire now know

it's possible to defeat the
most powerful army in the world.

Despite the military losses,
Rome pushes forward

with an immense
public-works project.

Emperor Caracalla inaugurates a
new complex of thermal baths

in 216 A.D.

-The huge scale and luxury
of the Caracalla Baths

demonstrated the prosperity
of an empire

that had recovered its strength

and filled
its financial coffers.

The 11-hectare baths
were the largest in Rome

at the time --
a gigantic construction

built with amazing
technical prowess.

Building huge vaulted ceilings
and, at the same time,

ensuring that they would resist
the heat and humidity

was a masonry nightmare.

-The thermal baths are central
to life in Ancient Rome,

serving as important locations
for socializing.

Most cities and towns throughout
the empire have at least one.

But each bath is also
a dangerous place,

where germs are spread
and epidemics take hold.

-The emperor created
an environment

that was completely controlled,

as the water and air
temperatures were regulated.

People came in big groups
to meet up,

look after their well-being,
and have a healthy lifestyle,

which was important
to the Romans.

But from our modern
point of view,

this hygiene was deceptive,

because it didn't take
into account microorganisms.

Bathing in the same water,
which was not chlorinated,

purified, or filtered,

meant that everyone shared
the same germs

and the same
intestinal parasites.

The baths inevitably

contributed to the spread
of diseases in the city.

-In 251 A.D., a second pandemic,
likely a hemorrhagic fever,

starts in Alexandria, Egypt,

and sweeps across
all of Ancient Rome.

-Just like in
the Marcus Aurelius period,

there was a correlation
between the disease

and the military problems
on the empire's borders.

But, in some ways,
from the year 250 onwards,

the danger to the empire
was more serious than before.

The enemies really forced
their way through.

Pillaging was rife
and more extensive,

and the stakes for the army
were more serious.

Barbarian invasions led to
a greater need for security

in the empire's provinces.

This security emanated
from the emperor and his armies.

But since there were
simultaneous

and multiple front lines

and one emperor
couldn't be omnipresent,

the regions would set
about choosing their own.

♪♪

It came about that three, four,
or more emperors co-existed

for brief periods of time.

So, along with defeat
came civil w*r.

-For the next 30 years,

a succession of emperors
and usurpers leads the empire,

most only in power
for a few months

and often stationed
with their troops

far from the capital.

The empire remains fragmented

until the end of
the 3rd century,

when a series
of military victories

and reforms unites
the empire once again.

But this calm will not last.

-In the 2nd century,

the outer limits of the
city of Rome weren't very clear.

It was Aurelian, in the 270s,

who decided to fortify the city
by building a wall around it.

♪♪

It was a sign of the concern
that was weighing on the empire,

because they knew
that the barbarians,

as well as the
Goths and the Alemanni,

were descending on Italy
from the north

time and time again,
threatening Milan,

and Rome could be next.

-But the new walls offer
only limited protection,

and the city remains
an easy target for Germanic

and Eurasian enemies.

Just 30 years later,

the empire's seat of power
moves east to Byzantium,

located at the passage

between the Mediterranean
and the Black seas.

The new capital is closer to the
most dangerous enemies

and easier to defend if invaded.

But the move and the division
between the eastern

and western
territories of the empire

is another sign
that Ancient Rome's strength

is slowly fading.

And with barbarian attacks
increasing

and political control fractured,

a new danger threatens
the empire --

climate change.

Today, scientists are
finding evidence

in the Czech Republic that shows
significant fluctuations

in temperature and rainfall,
just when Rome was already weak.

-All plants that live for
more than one year

outside the tropics,

so where we have
a seasonal cycle

in the climate system,
they produce a growth layer.

We call it a ring.

And since most of the plants

that are of interest for us
are trees,

we call them tree rings.

♪♪

And depending on
the growth conditions,

if they are favorable
or less favorable,

the ring
will be wider or narrower.

So we are basically able to see
the fingerprint

of the environment and climate

captured in
the tree-ring sequences.

[ Grunting ] So, I expect about

80 to 100 rings

on this oak tree,

so we would basically go back

over most of the 20th century.

♪♪

If we take a core sample,
we know the outermost ring,

just before bark.

So, the ring that was produced
in this summer

has the date 2021,

and then we just count
the years back.

-The climate data
that scientists collect

from the tree rings can
stretch back several centuries,

depending on the age
of the tree.

This is the first step
in a process scientists will use

to understand
the climate of Ancient Rome.

The next step is to look
at samples from the oldest wood

they can find.

-Go around this one.

The main timber
here in the middle looks good.

This old windmill here
is dating approximately

in the beginning
of the 18th century,

so it's roughly 200 years old.

By then, the material,
the oaks that were used

to build this construction,

are again about
150 to 200 years old.

So that means we are getting
back with the tree rings,

with these oak rings, almost
300 to 400 years back in time.

♪♪

We need many, many, many rings,
rings from many trees.

So that's why we are not only
taking one or two cores

from this construction here --

we will likely extract 20 to
30 cores from individual oaks.

♪♪

-Finding wood 2,000 years old
requires a visit

to archaeological dig sites,

like this medieval well
in the Czech city of Brno.

It dates from the 12th century
and contains a rare resource --

partially fossilized wood,

preserved in the ground
for centuries.

♪♪

But a new discovery takes
the scientists

even further back in time.

♪♪

-Gravel pits are
a particularly useful source

for such old subfossil material

because the trees must be buried
under anaerobic conditions.

So they are somehow in the
gravel below the water table.

And you see,
we are here in a very flat area.

So, the river was meandering,
changing its bed,

over the last centuries
and millennia.

The dead trees will fall in
the water and they get buried.

We don't know how old
the material is.

It can be between 1,000
and 8,000 years before present,

so there is a huge range
of possibilities.

And it is so important because
this is the material

that really extends our
oak chronologies

the furthest back in time.

-For this study,
dendrochronologists collect

hundreds of samples
of oak trees,

without knowing which historical
time period they may be from.

At the Mendel University
in Brno,

each of these samples
is carefully sanded

so that their rings
can be highlighted

and precisely measured.

[ Beeping ]

-Once this is done,
we start a process, a technique,

that is called cross-dating.

[ Clicking ]

With enough overlap
between the different sources,

from the living material
to the relic wood,

the historical timber,

later on,
the archeological wood,

and the subfossil one,
if we have enough overlap,

if the tree rings match,
if they fit together,

we can absolute date
all to the historical part.

-These curves show
the variations in the width

of the wood rings through time.

Each curve overlaps,

creating a timeline
that stretches back

centuries and millennia.

-Once we have all these tree
rings together and we can say,

"Ah, this ring is the year 1258,
this ring is the year 505,"

we take the wood
that is absolutely dated,

we cut the material
with a small knife --

have to be very careful that
no material from the previous

and the next ring
is included in this probe.

So, we talk about thousands
and thousands of small probes,

and then the process starts.

We extract the cellulose pure.

We h*m* the cellulose

so that
we have a very h*m* mass,

put it in a silver
or tin capsule,

and then we have two samples
per tree ring.

One we're gonna use for carbon,
one for oxygen.

-The carbon and oxygen levels
from the samples

tell scientists about historical
temperatures and rainfall

that enable them to create
an accurate picture

of plant-growth conditions.

-So, if we start
in the Roman period --

so let's say 100 years BC

to about 150, 180 years
Common Era --

we see this was
generally dry period.

Dry means, for us,
it was likely also warm.

One could say it was favorable.

And it was less fluctuating,
so that's an important thing.

Independent of warm or cold,
it was more stable.

And then we enter a period
around 200

where fluctuations kick in.

In this case,
it was getting wetter.

Wetter and
potentially also cooler.

And these fluctuations are
always unfavorable,

because societies are not able
to adapt to them

if they are too fast.

And they are unpredictable.

-The data from the tree rings
indicates that

after several centuries
of relatively mild temperatures,

a period known as
the Roman Climatic Optimum,

the climate in the empire
began to cool.

Cyprian, a writer who was
also bishop of Carthage

in the 3rd century,
described a world where

the sun's rays were less bright
and harvests less abundant,

"Only a pale old man
on the verge of his grave."

And the empire's problems
continue to mount.

With the cooler temperatures,
Eurasia's nomadic tribes

move west into Eastern Europe,

in hopes of finding more
hospitable land for agriculture.

The Huns,
a formidable adversary,

begin attacking
the empire's eastern border.

Again, tree rings
provide the evidence

for understanding
these westward migrations.

-In addition to our research
in Central Europe,

we also spent much effort

with our Russian colleagues
in Southern Siberia.

♪♪

So, this is
the great Altai region

at the border between Russia
in the north,

Mongolia in the south,
China in the southwest,

and Kazakhstan in the west.

♪♪

-The present-day Altai Forest
starts at an altitude

of 2,400 meters.

We can start from there
and go even higher.

♪♪

-So, the Altai is particularly
important for us to reconstruct

summer temperatures
because we find very old living

and relic dead trees
at the upper tree line.

♪♪

There is a reason
why they can't grow higher --

because it's getting too cold.

So even small changes
in summer temperature

will leave a distinct signal
in the tree rings.

So the tree rings are almost
like a thermometer.

♪♪

-The natural conditions in
high altitudes are characterized

by extremely low temperatures.

And these temperatures prevent
the wood from decomposing.

♪♪

Also, very often
in mountainous zones,

dead wood doesn't lie
on the ground,

but on stone,

which also prevents
the destruction of the wood.

♪♪

-Once the
Russian scientists finish

collecting the wood,
they travel to

Novosibirsk State University
in Siberia,

where the samples
will be dated and measured.

The data is then sent
to the University of Cambridge,

in England.

-Very interestingly,

the summer temperature
reconstructions from the Altai,

so from Inner Eurasia,
which is about 5,000 kilometers

east of the European Alps,
are very similar.

[ Beeping ]

♪♪

So we have evidence for a more
stable, warmer Roman period,

and around the 2nd century A.D.,

temperatures become to be
more variable,

so there is more fluctuation.

Past agricultural systems were
pushed towards their limits,

and nomadic steppe empires --

those that we know
from Inner Eurasia --

were most likely
affected in a way

that they just started to move,
to migrate further distances.

♪♪

-So, here, we're at
an archaeological site

called the Kuraika Cemetery.

It corresponds perfectly with
the historical era of the Huns.

♪♪

-The Altai has always been
a territory which one could call

a crossroads
for different populations.

It's a territory where we find
traces of nomads

from all eras,

nomads who came
one after the other

over several millennia.

[ Shouting ]

When a cold snap happened

and the climate graph indicates
a drop in temperatures,

we can see that people migrated

and the Altai territory
became depopulated.

In general,
people left this region

because farming conditions
were deteriorating.

-Once the Huns make it to
the eastern edge of the empire,

they discover the region
has already been settled

by nomadic tribes
from Northern Europe.

Smaller groups, like the Goths,
crossed the Danube

and settled in the Balkans
and north of Greece,

in present-day Bulgaria.

-They traveled right across
the Russian plain,

along the Volga River,

turned south towards Crimea
and the Black Sea,

and encountered barbarians
well-known to the Romans --

the Goths and the Sarmatians --
and fought them.

The barbarians neighboring
the empire found themselves

caught between
the hammer of the Huns

and the anvil of the empire
and asked Rome

if they could be
integrated into their territory.

The Goths were not
at all welcome

once they crossed the Danube.

They found themselves exploited

by the greed of Roman officials
in the province.

So they decided to revolt.

-The Goths had hoped Rome
would annex their territory

and offer protection
from the Huns.

The Romans agree to provide
the Goths with security,

but taking advantage
of the group's vulnerability,

they also treat them poorly.

In 378 A.D., the Goths revolt.

In Adrianople,
northwest of Constantinople,

the Eastern Roman Empire,
led by Emperor Valens,

faces off against the Gothic
rebels, led by Fritigern.

Believing his forces
outnumber the Goths,

Valens goes on the attack...

a decision that proves fatal.

[ Shouting, clanging ]

The Romans
find themselves overwhelmed

by the enemy cavalry and reduced
to hand-to-hand combat.

It is the greatest defeat
in the history of the empire.

Tens of thousands of soldiers
are k*lled,

and the emperor Valens himself
dies in battle.

With this major defeat,
the Eastern Empire no longer

has the resources to support its
other half in the west.

Left vulnerable to attack
and more easily reached,

it is only a matter of time
until barbarian tribes

conquer the Western Empire.

The Gothic victory reveals Rome
has weaknesses

that can be exploited,

bringing its enemies ever closer
to the capital city.

No longer the seat of power,

the Eternal City is sacked
in 410 A.D.,

though battles in the west
continue.

Finally, when the Vandals
invade North Africa in 429,

the Western Empire
disappears altogether.

Well-armed and less exposed
to invasion,

the Eastern Empire in Byzantium
continues on...

until the beginning
of the 6th century,

when Emperor Justinian
sees a chance to get revenge

and reconquer lost territories.

But his military strategy fails
to consider a force

much stronger than
any of the barbaric tribes --

the climate.

-Let's imagine
we're in the year 535.

The eastern provinces of the
Roman Empire are doing fine.

They have a new upstart emperor,

who was born
in the western provinces,

who speaks Latin
as his native tongue,

and has a dream to reconstitute
the Roman Empire.

And he targeted as his
first goal to reconquer Africa.

Africa fell
almost in a matter of months.

The Roman Empire had reconquered
the richest breadbasket

of the western
half of the Roman Empire

and was poised
to now move on Italy.

In 536, they cross from Sicily
into the mainland of Italy

and start marching towards Rome.

And they're marching up
successfully

in the spring of 536,

when something entirely
unexpected happened.

The sun stopped shining
for a period of between

12 and 18 months.

A contemporary says
that at noon,

the strength of the sun
was about like that of the moon.

-What could have made
the sun stop shining

in the spring of 536 A.D.?

Was the constant darkness
why Justinian failed,

when the whole empire
seemed within his reach?

-Do you want to flat out
switch to...

-At the University of Maine,

scientists have identified
physical evidence

of how the climate
was shifting at the same time

Justinian set out
to expand the empire.

-...when there's
a small iron peak,

but a much higher sulfur peak.

-A unique team of
climate specialists

and historians
has come together to study

how a natural climate event

could have brought down
the Roman Empire.

♪♪

This large freezer inside
a University of Maine lab

holds an ice core,

which offers insight into what
happened in the 6th century.

-This piece is about
60 meters deep.

We keep it in our freezer
at temperature minus-25 Celsius.

And right now,

I'm preparing this ice
for laser-ablation analysis.

I'm scraping the top part off
to remove any contamination

and make the surface flat,
as flat as possible.

-This ice core serves as a
record of the climate in Europe

for the last 4,000 years.

Scientists retrieved it
from a mountain peak

on the border of
Switzerland and Italy,

in the heart of what
was once the Roman Empire.

-Up until now, most of the great
ice-core work

has been done in Antarctica.

There, the technology is
perfectly adapted to ice cores

that, as in Greenland,
are 3 kilometers long.

In Europe, the situation
is completely different.

The ice core, from today
to bedrock, is 72 meters.

And the technology
was not yet established

which would allow one
to see the patterns in ice

that was so heavily compressed.

The Climate Change Institute,
under Professor Mayewski,

has perfected a new instrument

which allows one not to measure
100 times in a meter,

but up to 40,000 times.

♪♪

-The remarkable thing about
this instrument

is that it uses a laser
to collect the sample.

And you can actually see it
on the screen here.

It almost looks like a worm
moving along.

What it's actually doing is,
like a tiny jackhammer,

poking away,
flaking off chips of the ice.

Once those pieces of ice
fly off,

they get incorporated in a gas.

And that gas then takes
the sample to this instrument,

which is capable of measuring
very, very low concentrations

of things like
copper, lead, sodium.

Every single one of these has
a different story

about the climate,

about human activity,
a variety of things.

-Once they've identified
the area of the ice core

that corresponds
with the year 536,

scientists find a higher level
of sulfur than is normal --

evidence of a volcanic eruption.

They also find volcanic
glass dust in the core sample,

which allows them to locate
where the eruption took place --

Iceland.

But would this volcano have been
enough to stop Justinian's

military campaign?

-Determining the magnitude
of the eruption

is hard from an ice core,
except if you take a look at

the sulfur, the bismuth,
and the tin levels,

they're remarkably high
for the last 2,000 years.

So that would tell us that
the 536 was a very big event.

[ Rumbling, expl*si*n ]

-The eruption threw
so much sulfur dioxide

into the atmosphere that,
in the years following,

temperatures drop by
about 2 degrees --

one of the coldest periods
of the last 2,000 years.

-And so, 536 --
that's the beginning.

Another volcano in 540,
another one in 547.

It gets colder and colder
and less and less appealing

in terms of crop growth.

And then, in 541,

in the Nile Delta,
there explodes a new pathogen.

-In 541 A.D., an epidemic of
unprecedented virulence

changes the history
of the empire forever.

Today, archaeologists
are searching for traces

of this epidemic
all across Ancient Rome.

Here on the island of Maguelone,
near Montpellier, France,

they suspect the epidemic
caused the collapse

of a Mediterranean village.

-This is a magical place.

It's a cathedral built
on an island.

It's an island very close
to Montpellier,

not far from the mainland,

situated between
the marshland and the sea.

It's surprising, because today,
we can just drive across,

but in the past, this island
was separated from the mainland.

♪♪

-We've found Byzantine-style
weights and measures,

suggesting that there had been
spice merchants here,

trading across
the Mediterranean.

♪♪

-The first thing you would see
on arriving on the island,

probably, were the boats.

There must have been
a whole flotilla of seacraft --

smaller boats
and flat-bottomed boats

for navigating the marshes.

♪♪

We suspect that they were
storage depots, mainly that.

It's likely that there was trade
in sheets, wool, cheeses,

and all sorts of goods
that don't leave

archaeological traces.

♪♪

-In the years 560 to 580,
it's noticeable

that the site
became depopulated,

and we discovered
some rather strange things.

We found corpses,

makeshift burials,
which were really just bodies

thrown into the rubble
of demolished buildings.

There was an epidemic situation
or a w*r situation.

In any case, the occupying power
was in a phase of decline.

♪♪

We're trying to shed light
onto some of the darker

aspects of this age covering
the 5th and 6th centuries.

It's the key period between
the Roman and Byzantine worlds

and the emerging medieval world,

with the creation
of the Germanic kingdoms.

-So, here, there are two femurs,
the thigh bones,

pointing downwards.

The individual doesn't seem
to have been buried

horizontally on the site,
as would normally happen.

You can see it clearly here --
there are these parts,

which are lying
more or less flat,

but when you get
to these bones here,

they're pointing down
into the earth.

The body might have just
been thrown away like that,

like you throw rubbish
into a tip.

♪♪

-Occasionally,
the bodies were thrown away,

literally thrown
into a rubbish dump.

Sometimes,
they were buried carefully --

no signs of wealth or caskets
or any construction,

but with a certain
amount of care.

♪♪

-We've also found, for example,
a body buried face-down,

which is a terrible punishment
for a Christian,

since it signals absolute
deprivation from eternal light.

♪♪

-Oh, look -- here's a tooth.

-Often, it's teeth

which are the best-preserved
parts of ancient corpses.

Sometimes, that's all we find
because they fossilize so well.

What's wonderful about this
is that they're all there.

And that will enable us,
thanks to DNA,

which is so well-preserved
in teeth, to study diseases,

in particular the plague,
to look for the plague bacillus.

♪♪

-Numerous burials in disarray,
buildings destroyed,

and the village deserted.

Why was this apparently
prosperous town

suddenly abandoned
during the 6th century?

♪♪

Answers to this question
can be found

at the Max Planck Institute
in Germany,

where a team specializing
in the study of diseases

found in archaeological remains

is now identifying pathogens
from Ancient Rome.

Bones are being collected
from dig sites all over Europe.

-So, what we usually take
as material to start with

are actually teeth
from the past,

from a person that has died,

potentially of an ancient
infectious disease.

And a tooth is so interesting

because inside the tooth,
you have dried blood,

and inside the blood,
of course,

the pathogen might
have been circulating.

So, how do we get that out?

We have to basically cut
the tooth open.

So, we make a cut and then
we drill inside that cavity

and remove bone powder --

little pieces of bone that,
on its surface,

might have the DNA
of the pathogen bound.

♪♪

So, what we then next do is
we have to somehow

get the DNA out of that
bone powder from the tooth.

So, we do that by
dissolving it in a liquid.

So, what you then
have is something we call

the DNA extract,
which is the extracted DNA

from the ancient bone,

where you then have little
pieces of DNA of the person.

You have maybe the pathogen
that has k*lled the person.

But the majority of
the DNA that we get

from an ancient skeleton
is actually not from the person

and it's not from the pathogen,
but it's from the environment,

because the skeleton
has been in the ground

for more than 1,000 years,

so it accumulated DNA of many,
many micro-organisms.

You really have a soup of DNA,

and just a tiny proportion
of that DNA

is actually from the pathogen
that you are interested in.

It's maybe something like
0.001% of the DNA

is actually the pathogen DNA
that we are interested in.

[ Beeping ]

-In order to find
a specific pathogen,

the DNA from the tooth sample
is broken into many segments.

The segments are then compared
with the DNA of known diseases,

eliminating possibilities
like tuberculosis or typhus.

♪♪

In the tooth sample,

the scientists
identify Yersinia pestis,

the bacteria that causes
the Black Plague.

-We have been looking for
Yersinia pestis from the time

of the Justinianic Plague,
so from the 6th century.

We have actually screened
hundreds of human remains

from the time period
to see where in Europe

you could find plague
during the time of

the Justinianic Plague.

And we were actually
quite surprised

because we were finding it
in individuals from Iberia,

so from modern-day Spain,

from France,
from Germany, from England,

so from large parts
of Western Europe.

In about a dozen or so
ancient human remains,

we found Yersinia pestis DNA
to be preserved,

and we could reconstruct
entire genomes

of those ancient plague
bacteria.

-Gradually,
scientists draw a map of where

they're finding plague,

noting that, based on the
succession of waves of illness,

the epidemic lasted
roughly a century.

In Constantinople, an estimated
300,000 people died

during the first year
of the outbreak.

Despite its vast territory
and immense power,

the Roman Empire
could not

withstand centuries
of mass disease

happening at the same time

that the climate was cooling

and crops were failing.

The process took
several hundred years,

but ultimately,
Ancient Rome may have

fallen as a result
of forces far greater

than military
or economic power --

perhaps a lesson about

the limitations of humanity

in the face of Mother Nature.

♪♪