Original subtitles

On the night of the 21st of February 1978, on a residential street in Mexico City, a

group of workmen were digging through the hard asphalt of the road.

They worked for the Mexico City electric company, and their job was to run cables across the

street and through the whole neighbourhood.

At first, it seemed like just another day at work.

But then, just over two meters into the earth, their diggers struck something.

It was an enormous piece of stone.

As they excavated further around it, they saw that this stone was carved in ornate and

intricate patterns.

They quickly notified the archaeologists at Mexico s National Institute of History and

Anthropology, and all construction work in the area was stopped.

Flocks of archaeologists descended, and excavations began to discover what this remarkable stone

was.

The more they uncovered, the clearer the picture became.

This was a carved stone disc measuring over 3 meters in diameter.

On its surface was the image of a woman, a goddess, naked and decapitated, surrounded

by snakes and skulls, and wearing a crown of feathers.

This was a depiction of a god named Coyolxauhqui, who was worshipped by the ancient indigenous

people of Mexico, who today we call the Aztecs.

The discovery of this stone sparked an outburst of interest in what else might lie beneath

the surface of Mexico City.

The president of Mexico issued a decree ordering the entire city block to be demolished and

excavated.

In all, thirteen buildings in the neighbourhood were torn down.

The more they uncovered, the more excited the archaeologists became.

They found that the stone disc had been placed at the base of an enormous set of stairs which

led up to a platform on which the ruins of a great pyramid once sat.

This was the main temple of a city that had once stood beneath the streets of Mexico City

and had been completely erased by time.

This city was called Tenochtitlan, and it was once the heart of a powerful empire.

The excavations in Mexico City would go on for another four years.

Every day, its people would come and watch as the ruins of a buried civilization rose

out of the familiar streets.

As they watched, many of them must have wondered; who were these people who once lived on the

land beneath our feet?

How had they built such phenomenal constructions of such incredible craftsmanship?

How could such a large and advanced society simply disappear beneath the earth?

My name s Paul Cooper, and you re listening to the Fall of Civilizations Podcast.

Each episode, I look at a civilization of the past that rose to glory and then collapsed

into the ashes of history.

I want to ask, what did they have in common?

What led to their fall?

And what did it feel like to be a person alive at the time who witnessed the end of their

world?

In this episode, I want to look at one of history's most incredible stories; that s

the rise and dramatic fall of the Aztec Empire.

I want to explore how the Aztecs overcame the odds to create one of the Americas' largest

indigenous empires.

I want to explore how they reacted to one of the most astonishing and terrifying encounters

that any society has ever experienced.

I want to tell the story of what happened to cause the dramatic and final end of their

age.

Up until around 66 million years ago, the planet Earth was a very different place to

the world we know today.

In those days, its surface was home to enormous reptiles known today as dinosaurs.

If we could walk across the continent in those days, we would see a landscape covered with

ferns and swamps, dotted with enormous primeval pine forests.

Small winged Pterodactyls flitted in the air, and enormous dinosaurs like the horned Triceratops

travelled over the plains.

In the forest, fearsome packs of Velociraptors hunted for their prey, and huge carnivores

like the Tyrannosaurus lumbered among the trees.

But it s in the sky that perhaps the most impressive of these creatures could be seen.

Quetzalcoatlus was the largest flying animal ever known.

It had wingspans of over 15m, larger than a modern fighter plane.

Because of their enormous size, they rarely landed, and spent most of their lives soaring

in the warm upcurrents rising off the sea, making migratory journeys back and forth across

the Atlantic ocean, which was then only about half the distance across.

Then one day, a new star appeared in the sky.

It would have been dim at first.

But as the days went by, it got brighter.

Only a day or two would have passed before this light would look like a second sun.

Then a blinding flash would have lit the skies of the entire Western Hemisphere.

In less than the time it takes to blink, an asteroid measuring 11km across, or about the

size of Mount Everest, impacted the earth s surface right on the coast of Southern Mexico.

The energy released was around 100 million megatons, or the equivalent of the entire

world s nuclear arsenal being detonated all at once about 15,000 times over.

The earth s surface around the impact would have rippled like water, under a magnitude

ten earthquake.

The asteroid itself was instantly vaporized and sublimed into a core of superheated plasma

over 10,000 degrees Centigrade or twice the surface temperature of the sun.

Scorching winds of more than 1,000km an hour blasted out over the continent, and tsunamis

of up to 200m high thundered into the coasts and washed over the land for distances of

100km.

Wildfires burst into light around the world as burning debris began to rain down on the

earth, and plumes of vaporized rock dust cloaked the planet in a dark shroud that blocked out

the sun for years.

In parts of the earth, pellets of glass began to rain from the sky.

Much of the life on planet Earth would not survive this event.

All large dinosaurs quickly fell into extinction; the Tyrannosaurs and the Triceratops, as well

as that enormous flying creature Quetzalcoatlus.

Over half of the plant species in North America were wiped out, and for years afterwards,

only mushrooms and other fungi could grow, feeding on the decaying matter of the world

s forests.

Only small land animals like snakes, lizards, and snails survived, many of them by burrowing

into the ground.

Crawling among the dust and ash of the world s ruins were also the small, rat-sized mammals

from which every person you know today is ultimately descended.

Today, the enormous circle of the impact crater can still be detected around the town of Chicxulub

in Southern Mexico.

The crater is 150km wide, and gouged a hole several kilometers deep into the earth s crust.

Over the next 66 million years or so, the earth would undergo some dramatic changes.

The continents of the Americas had already been drifting away from the landmass of Europe

and Africa for over 100 million years as the earth s plates ground and cracked around each

other.

If you went far enough back, it would have been possible to walk from Nigeria to Brazil,

from Morocco to New York, or from Spain to Canada.

But now the world was split into two great landmasses; one known as Afro-Eurasia, containing

Africa, Europe, and Asia, and the other known as the Americas.

Driven by the powerful currents of molten rock that circulate in the planet s mantle,

the earth s crust tears apart in the middle of the Atlantic Ocean.

Meanwhile, the North and South American continents move westwards, all at about the rate your

fingernails grow.

Since the time of the Chicxulub asteroid, the width of the Atlantic Ocean has grown

by about 1,300km.

The west coast of the Americas from Alaska to California, down the coast of Mexico, through

Colombia, Peru, and Chile, are the cutting edge of their continental plates.

As they forge west, they force the Pacific Ocean floor down beneath them, crumpling as

they go and forcing up huge ranges like the Rocky Mountains in North America and the Andes

in the south.

The titanic forces involved in this process mean the whole length of the continental coast

is a hotspot for earthquakes and for volcanoes.

The landscape of what is today Mexico is dominated by these volcanoes.

In the south of the country, a range known as the Trans-Mexican Volcanic Belt has burst

up over the last 20 million years, forming a dramatic range of snow-capped peaks.

Between these mountains, a highland plateau has formed where solidified lava flows have

washed over one another.

Today, this is known as the Valley of Mexico.

The Valley of Mexico is a dramatic landscape.

It sits at an altitude of over 2,000m, while the active volcanoes that form its walls can

soar up to 6,000m.

The land here is fertile and water is plentiful.

Rain and meltwater from the mountain snows flow down the sides of the valleys and into

rivers, gathering in the floor of the basin in an enormous lake known as Lake Texcoco.

Lake Texcoco was huge.

It was about 40km in width and about 80km in length, bordered by a marshland of reeds

and rushes.

In winter, migratory birds from as far as Canada also came here to enjoy the warmer

weather.

In the 66 million years since the Chicxulub asteroid, the small, rat-like creatures that

survived had also undergone a few changes.

By this time, they had transformed generation by generation, as gradually and unstoppably

as the continents.

They had now diverged into the huge variety of mammals that we know today.

Horses evolved in North America about 3.5 million years ago, and in times of low sea

levels, they crossed over into Eastern Russia, spreading from there across Asia and the rest

of the Afro-Eurasian landmass.

Other animals crossed in the other direction.

Giant Colombian mammoths, creatures weighing over ten tons, walked from Asia into the Americas

and spread down as far as Southern Mexico.

The last time these sea levels dropped was during the last Ice Age that began around

33,000 years ago.

During this time, a land bridge emerged between the continents of Asia and the Americas.

Humans used this bridge to follow where the mammoths had gone before, crossing from Asia

into the Americas.

They travelled south from there, setting up Stone Age cultures wherever they went, and

they arrived in the Valley of Mexico probably around 12,000 years ago.

Around this time, the horse went extinct in America due to a combination of changing climate,

collapsing ecosystems, and possibly human hunting for food.

Then, around 10,000 years ago, the last Ice Age came to an end.

Sea levels rose and the land bridge between Asia and the Americas sank back beneath the

waves forever.

Horses would never return by natural means to the Americas.

The human populations of the two sides of the world were now separated.

One day in the future they would meet again, and this is the story of how that happened.

The earliest humans in the Valley of Mexico were hunter-gatherers.

They found vast herds of mammoths roaming the pine forests bordering Lake Texcoco, and

over the next millennia, hunted them to extinction.

Today, the earth of the valley is still littered with their bones.

Agriculture began around the lake about 7,000 years ago, with humans following the natural

patterns of the lake s flood cycle.

Various cultures made their home here over the millennia, coalescing into larger and

larger settlements, and by the year 1,200 BC, a number of large villages began to rise

around the valley.

To the north, the lands were tough and arid, and if you traveled far enough, you'd reach

the baking deserts of Chihuahua in northern Mexico.

Life in the desert was hard, and so over history, countless migrating tribes and nomadic groups

traveled south into the Valley of Mexico where water was plentiful and food easier to find.

So while young cities began to rise up on the shores of Lake Texcoco, wave after wave

of newcoming people also arrived.

The population of the valley swelled, cultures intermingled, and more complicated forms of

society began to take shape.

In the early centuries of the first millennium, the valley began to be home to some of the

first cities.

Of these, one would soon rise to unprecedented size and power.

This city was called Teotihuacan.

We ve encountered Teotihuacan before, in our third episode on the Mayans.

Its people built towering pyramids and stately processional avenues in their capital, monopolizing

a kind of green obsidian that could be found nowhere else.

Its influence spread far and wide, reaching down into Central America and interfering

in the politics of Mayan kingdoms.

This city had an enormous influence on the region, but we know virtually nothing about

its people; who they were, what language they spoke, or even what happened to them.

Archaeology shows that around the year 550 AD, the entire city, all its temples and palaces,

were burned.

The city went into a sharp decline and its towering pyramids fell into ruin.

But its cultural influence would live on.

Teotihuacan played a similar role in Mexico as the ancient Greeks did for Europeans.

They inspired new cultures and left a mark on their religion, society, and art.

But if Teotihuacan s people were the Greeks, then the Romans of this region were the Toltecs.

After the collapse of Teotihuacan and the fall of the Mayan cities in the south, the

Toltec Empire was the dominant force in central America, ruling from the city of Tula.

Just as Rome openly admired the culture of the Greeks, the Toltecs modelled themselves

on the great fallen empire of Teotihuacan.

They spoke a language called Nahuatl which would quickly become the predominant language

of the region.

It s clear they were outstanding craftsmen and artisans.

Their artistic abilities were so famed that in Nahuatl, the word Toltec would come to

be used simply to mean artist.

But before long, for reasons that we don t entirely understand, the city of Tula was

also abandoned, and the Toltec Empire followed Teotihuacan into ruin.

This is where our story really begins.

I think it s worth taking a moment here to talk about the sources that we have about

life in the time of the Aztecs.

The word "Aztec" is not a word those people would have used about themselves.

It's a later invention.

They would have called themselves Mexica.

We actually have a wide variety of sources to draw from, many of them written by Mexica

people who actually witnessed life before contact with Europeans.

But one problem for historians is that these eyewitness accounts were all written after

contact, and most several decades after the events.

One of the main sources for these years was the work of the Spanish churchman Bernardo

de Sahag n, who some have called the first anthropologist .

He arrived in Mexico in the year 1529 and spent the next 50 years learning the language

of Nahuatl, as well as studying the culture and history of its indigenous Mexica people.

In the 1550s, 30 years after contact, he gathered together as many older Mexica people as he

could find who still remembered the age of the Aztecs.

He wrote down their memories and collected them in an extraordinary book called A General

History of the Things of New Spain, or the Historia General.

The most famous section of the Historia General is known as the Florentine Codex.

It s a manuscript consisting of 2,400 pages, organized into twelve books, and containing

over 2,500 illustrations drawn by native artists.

Bernardo de Sahag n recorded the text in both Spanish and Nahuatl.

On this episode, we re joined by Yan Garcia, a native speaker of Huatesca Nahuatl from

Mexico, who will help us to hear the sounds of the Florentine Codex in its original Nahuatl.

The Florentine Codex is an incredible account of the culture, religion, society, and history

of the Aztec people.

But it s important to remember that it was created under the supervision of a European

priest who had his own set of agendas.

The people he interviewed were remembering events and details from a distance of many

years, and it's impossible to know how much they were telling Sahag n what they thought

he wanted to hear.

This all complicates it as a reliable source.

Another key character in recording the Mexica experience was a Dominican monk called Fray

Diego Duran.

Duran was rare among the Europeans, most of whom never learned the indigenous languages

of Mexico.

He was raised from an early age by servants who spoke Nahuatl, and grew up a fluent speaker.

He wrote a book called The History of the Indies of New Spain, but he died without it

ever being published, since he faced fierce criticism during his life for what other Spaniards

saw as his excessive sympathy for the indigenous Mexicans.

Towards the end of the 16th century, a handful of indigenous men also wrote down their histories.

Don Fernando de Alva Ixtlilxochitl is one example.

He was descended from the last king of the Aztec city of Texcoco, and although far-removed

from the events described, he had access to some Aztec books that had been kept a secret

from the Europeans.

So, these are the sources we have to rely on, each one of them potentially flawed and

fragmentary.

As a result, trying to find out the truth of this period can seem like navigating a

hall of mirrors, reflections of reflections, leading us around in circles.

But combining these accounts with archaeological evidence does allow us to piece together some

of the major events of the Aztecs rise to power.

Our story begins around the year 1,300 AD.

By this time, the Valley of Mexico looked like a very different place.

The vast ruins of Teotihuacan and Toltec civilization could be seen all around, crumbling into the

earth.

The dozens of small villages around the lake had by this time grown into powerful city

states in their own right.

Each one had a set of tall pyramid-shaped temples at their hearts.

A thick traffic of canoes, some of them holding up to 30 people, criss-crossed the lake, bringing

trade and goods to the markets in each of these cities.

The political situation had changed, too.

In the vacuum left by the Toltecs, a people known as the Tepanecs had grown to exert power

over the other cities of the valley.

They ruled from the city of Azcapotzalco which rose on the western bank of the lake.

This early form of empire had grown to an impressive size.

At this point, at least 40 other cities paid tribute to them and sent soldiers to fight

in their armies.

It was at this time, around 1300 AD, that a new band of migrants arrived in the valley.

These were what the people here called chichimecas, a word that in Nahuatl means barbarian or

savage, and it was usually applied to the groups of wandering nomads who often arrived

in the valley from the northern deserts.

This group claimed to have come from a land which they had been forced to flee, but which

no one else had ever heard of.

They called this mysterious place Aztlan.

They said they had been wandering in the deserts for many years, searching for a new place

to call home.

They called themselves the Mexica, but today we call them by a name derived from their

mythical homeland Aztlan.

These were the people who would one day be called the Aztecs.

We can imagine how these weary desert travelers must have felt when they crested the hills

and saw the wide, green valley of Mexico stretch out before them.

They would have seen the cities scattered out around the lake, glittering like jewels.

They must have thought that surely somewhere in this bountiful place they could find a

place to call home.

But they were soon to be disappointed.

The steady flow of people migrating south into the valley had increased the population

density.

Virtually all of the land in the valley had already been claimed by one city or another

and wherever they went, the city-dwellers sent them away.

Part of the reason for this is that the Mexica seem to have been a rough bunch.

They didn t wear the embroidered clothes of the city-dwellers or have any of their sophisticated

manners.

Their years of fighting to survive in the wilderness had made them tough.

They worshipped a fierce god, a warlike deity known as Huitzilapotchtli whose name meant

hummingbird of the south .

While none of the valley s city-dwellers would let the Mexica settle down in their lands,

they did see one obvious use for them.

Several cities offered to give the Mexica food in exchange for their services as mercenaries.

So, this nomadic people wandered about the valley, agreeing to fight for whoever would

pay the most, and dying in other people s wars.

But they must have still yearned for a real place that they could call home.

After 25 years or so of fighting for other people, the Mexica must have realized that

no one was going to give them a home.

They would have to build one for themselves.

But there was only one last piece of uninhabited land left in the whole valley.

It was a place so inhospitable that none of the other peoples had even bothered to claim

it.

It was nothing but a marshy strip of land lying some way out in the water off the western

shore of Lake Texcoco.

The Mexica built canoes and paddled out to this lonely stretch of land.

There, they managed to build a number of small huts and a simple altar made of reeds to their

god Huitzilapotchtli.

It was an incredibly humble start, but it was theirs.

Although they were not to know it then, this swampy village would grow in the space of

only two hundred years to become one of the world s greatest cities.

The Mexica named this settlement after one of their legendary kings who had led them

wandering through the desert, a man who had been named Tenoch.

So, this place would be called Tenochtitlan.

The city of Tenochtitlan expanded gradually at first.

From those original few huts, the Mexica soon used up all the space on their island.

But with their population growing, they would need to come up with a solution.

They began to build artificial islands out in the lake.

They would paddle out into the water on canoes and drive tall stakes into the shallow lake

bed, then pile earth in around them until the ground rose out of the water.

Over the years, these new islands spread out from the centre in a chaotic pattern, connected

by bridges and canals.

The island city of Tenochtitlan began to grow.

If you returned to see Tenochtitlan a century later, in the early decades of the 1400s,

the city would have been unrecognizable.

It would have looked something like Venice.

The city was now joined to the mainland by three great causeways branching out to the

north, south, and west.

These were broken in the middle by wooden drawbridges which were raised at night for

security.

To the east, the great expanse of the lake stretched out, although on a clear day it

was possible to just about see the other shore and the city of Texcoco that rose there.

Tenochtitlan was surrounded by island gardens called chinampas.

The Mexica built these by weaving together sticks and reeds to make underwater fences

which were then filled in with fertile earth.

They used these island gardens to grow all kinds of crops from maize, beans, and squashes

to tomatoes, chilli peppers, and all kinds of decorative flowers.

The farmers paddled between these gardens in their canoes, carrying sprouting plants

and tools, and bringing back the crops in baskets.

Since a number of mountain springs fed into Lake Texcoco, its water had an unusually high

salt content, and so the production of salt was another key industry of the area.

One 16th century Spanish observer named Pedro Martir described seeing the Mexica engage

in this practice.

They take the lake water, which is salty, and lead it through ditches into depressions

where they thicken it.

Once thickened, they boil it, and then form it into balls and loaves which they take to

markets or fairs to exchange for other things.

Only the subjects of the Aztec King have access to this salt, and never those who disobey

his commands.

As well as farming, the Mexica would have fished and hunted.

Migratory birds like geese were particularly abundant in the winter months, as the Spanish

visitor Ortiz de Montelano recalls.

There are great multitudes of birds on the Mexican lagoon.

There are so many that in many parts, it looked like a solid lake made of birds.

This happens in winter and the indians harvest many of them.

The Mexica also supplemented their diet with other sources of protein.

Among these were several species of insect, including one they called the axay catl, a

kind of marsh fly.

Another Spanish writer, Hernando Fernandez, writing in the 16th century, describes how

the Aztecs prepared this food.

The axay catl is a small fly, which in certain seasons is collected with nets from the lake

in such great quantities that great numbers of them are cut up and mixed together to form

little balls which are sold in the markets throughout the year.

The indians cook them in salty water wrapped up in maize husks, and prepared in this way,

they comprise a good food, abundant and agreeable.

Other sources of food include fish eggs eaten as a kind of caviar, and even the eggs of

the axay catl fly itself, which were laid in enormous numbers on the mudflats and reedbeds

of the lake.

In Nahuatl, these eggs are known as ahuauhtli, which loosely translates to wheat of the water

.

The Mexica ground these eggs into a paste, baked them into cakes, and flattened them

out in tortillas.

Both the axay catl fly and its eggs were made up of 60% pure protein, making them an exceptional

dietary source.

As a snack, the Mexica also liked one species of aquatic worms they called ocuiliztac, which

they toasted with salt.

With this abundance of available food and ingenious farming techniques, a population

boom took place in Tenochtitlan.

It grew in the space of only a century until it housed at least 200,000 people, larger

than either London or Paris at the time.

In fact, it was likely larger than any city in Europe.

It soon covered a rough square of around 3km on each side, and this rapid growth had a

transformative effect on the Mexica people.

The rough bunch of Mexica warriors who had first arrived in the valley would have now

been unrecognizable.

They were a sophisticated and settled people.

They successfully absorbed the old cultural traditions of the Toltecs and Teotihuacan,

adopting their culture of pyramid-building and stone-carving.

They welcomed craftsmen and learned people from all the other cities of the valley, absorbing

their customs and developing astonishing skills of engineering.

In 1418, the Mexica began the construction of a vast series of stone aqueducts, stretching

for 4 kilometers across the lake over a series of artificial islands.

These brought clean, fresh water right into the heart of the city.

The Mexica also built an enormous dam that helped protect the city from seasonal flooding.

Tenochtitlan was divided into a number of key districts.

In the north was Cuepopan, or the place where flowers bloom , and in the west, Moyotlan,

the place of the gnats .

The humble reed shrine that the Mexica first built had now been replaced by an enormous

pyramid standing at the head of a courtyard, measuring half a kilometer squared.

Each new king had expanded this pyramid, building around and on top of the existing structure

so that today you can still see the remains of its previous versions inside its ruins,

looking something like a Russian doll.

This is where the great stone disc with the image of the goddess Coyolshawkwee lay, waiting

to be discovered by those Mexico City electrical workers 500 years in the future.

That stone once formed the base of the steps leading up to this pyramid.

The city of Tenochtitlan was a place of pleasure and luxury.

It had a botanical garden and even a zoo where animals were kept, two innovations that Spanish

visitors later found remarkable since they had seen nothing of the kind back in Europe.

Drinking alcohol was strictly forbidden in Mexica society.

Punishments for being found drunk in public were severe and could even result in death.

Although, it s clear that many people did it anyway.

They drank something called pulque, a particular kind of milky alcohol brewed from the agave

plant.

If you walked the streets of Tenochtitlan in the 15th century, you might also see groups

of people eating hallucinogenic mushrooms or drinking them in tea.

These mushrooms were used widely by the Mexica for recreation, and especially among the poets

and priests for whom they took on a religious significance.

One piece of oral poetry recorded in the Florentine Codex is just one example in which the effects

of these narcotics were mentioned.

I have drunk fungus wine and my heart weeps.

On earth I have only pain.

It matters nothing.

We are all precious jewels of the god, strung on a thread.

We are all together jewels on his necklace.

One of the city's most remarkable sights could be found in the northern part.

Here, in the district of Tlatelolco, a great market was held.

This city in the lake had now become the great crossroads of all the trade in the region,

with boats coming from all the lakeside cities to sell their produce.

An enormous, colourful variety of food and other goods were brought from all over the

valley and beyond; cocao and bright green quetzal feathers from the south, obsidian

blades for everyday use, paper made from bark, as well as gold and silver from the north.

One extract from the Florentine Codex contains a list of all the foods eaten at just one

Aztec feast, and it gives you a sense of the variety that they enjoyed.

They ate white tortillas, grains of maize, turkey eggs, turkeys, and all the fruits,

custard apple, mamey, yellow sapote, black sapote, sweet potato, manioc, white sweet

potato, jicama, plum, jobo, guava, avacado, acacia, American cherry, and tuna.

Clothes and textiles were also sold in the great market of Tlatelolco, woven in all the

different colorful patterns that the Aztecs made.

They gave them all the different kinds of precious cloaks they carried, like those mentioned

here; the sun-colored style, the blue-knotted style, the style covered with jars, the one

with painted eagles, the style with serpent faces, the style with wind jewels, the style

with turkey blood or with whirlpools, the style with smoking mirrors.

The market was a social place full of hustle and bustle.

The Aztecs loved riddles, and while the canoe riders and market sellers mingled, they may

have laughed and exchanged new ones they d heard that week.

Some examples of these Aztec riddles have survived, and we can listen to some of them

now.

I ll leave a small gap between the riddle and their answer in case you want to pause

and try to figure it out for yourself.

What thing, what thing?

Ten stones with something on their backs.

They are the nails on our fingers.

What thing, what thing?

White stone from which green feathers are born.

It is an onion.

What thing, what thing?

A warrior in a house made of pine branches.

The eye, with all its lashes.

But amid the booming life of this city, there was also a darker side to Tenochtitlan which

would have been immediately apparent to anyone who visited it.

If you were a tradesman arriving in the market of Tlatelolco, it would have been hard to

ignore the vast pyramid rising from the district of Teopan; one shrine painted blue, and another

a deep, dark red.

The blue shrine was dedicated to the god Tlaloc whose name meant wine of the earth .

He was the god of rain and fertility, the god of life.

Other gods the Aztecs worshipped include Tezcatlipoca, the god of night, and the famous Quetzalcoatl,

the feathered serpent who is often depicted as a kind of flying dragon.

But the great red temple was dedicated to a very different god.

On the ornately carved steps, the stones would have been darkened by a cascading stream of

dried blood.

The culture of the Mexica had changed dramatically over the last century, but they still held

on to some aspects of their rough beginnings.

Among these was the continued reverence for the fearsome hummingbird god Huitzilapotchtli,

the god of the sun, the god of war and sacrifice.

The Aztecs believed that Huitzilapotchtli took the form of the sun and every day chased

his siblings, the moon and stars, across the sky.

They believed that if he ran out of the energy he needed to continue this chase, the world

would end.

There was only one way to supply him with that energy.

In the Aztec view, every living being had a fragment of the sun lodged in their heart.

They believed this is why the body gave off warmth and life.

They believed that cutting out the heart of a sacrificial subject and burning it in offering

to Huitzilapotchtli gave him the energy he needed.

For the purpose of these sacrifices, the Aztecs bred several animals including dogs, eagles,

jaguars, and deer.

Of course, they are most infamous for the sacrifice of humans.

Humans were sacrificed for religious purposes in various societies throughout American history.

In Mexica society, this was done in a wide variety of ways depending on which festival

was being celebrated.

But the most common was for a sacrificial victim to be brought to the top of one of

the pyramids in Tenochtitlan, and held down on a stone slab.

A priest would then take a sharp dagger made of the black volcanic glass obsidian, which

forms a cutting edge sharper than surgical steel.

They would plunge this dagger into the victim s chest, cut through the diaphragm, and remove

the heart.

Human hearts are powered by their own sets of self-driving muscles, and so would continue

to beat for as long as the supply of blood remained inside them, sometimes for as much

as ten minutes after being removed from the body.

These still-pulsating hearts were placed in a bowl and burned, allowing their energy to

return to the sun.

Meanwhile, the lifeless body left behind on earth was thrown down the steps of the pyramid,

where they were dismembered and fed to the animals in the city zoo.

Some ceremonies also involved elements of cannibalism.

It s impossible to know the full extent of this grisly practice before contact with Europeans.

A number of factors complicate this question.

The first is that the practice of human sacrifice was used by the Spanish as part of their justification

for the colonization of the Americas.

For this reason, they were inclined to exaggerate the number of people killed.

The Mexica themselves may have also exaggerated the numbers in their historical documents,

since boasting a large amount of sacrificial victims reflected well on their power and

status, and may have also served a propaganda purpose in frightening their enemies.

For instance, the Mexica claim to have sacrificed over 80,000 people in the year 1487 for the

dedication of just one temple.

While we have found some traces of sacrificial burial grounds around some Aztec temples,

we ve never found any evidence of the kinds of mass graves that this kind of slaughter

would produce.

So, we re left guessing as to how many people exactly may have died.

Another factor complicates matters when comparing the Aztecs to other comparable societies from

history.

That's the fact that sacrificed victims were usually prisoners of war, captured during

battle with rival states.

Warfare in the Aztec world was a highly-ritualized affair.

Wars began with a number of ceremonies and rituals, and would always take place in the

half of the year when farmers weren t needed in the fields.

The battles themselves were very different to those fought in other parts of the world.

Aztec soldiers were generally not aiming to kill their enemy on the battlefield.

Their main goal was to capture the enemy soldiers and bring them back to Tenochtitlan to be

sacrificed.

The incentives to capture rather than kill your opponents were huge.

All lower class boys were trained as soldiers from an early age, but they would not be considered

a true man until they had captured their first enemy for sacrifice.

After taking two prisoners, he would rise to the ranks.

He would be allowed to wear sandals into battle, and would be rewarded with a feathered cloak.

At four captives, the warrior would be promoted to the rank of jaguar warrior and would be

given an actual jaguar skin to wear into battle.

Jaguar warriors held a similar position to European knights.

A commoner who rose to this rank had now entered the nobility.

In fact, this was the only way any commoner could rise in social status.

If a jaguar warrior truly excelled and captured even more, he would be promoted to the rank

of eagle warrior.

These were the military elite of the Mexica and would go into battle wearing a beaked

helmet and resplendent feathers.

They were the most feared of all the Aztec warriors.

Because of these incentives to capture rather than kill, some historians have argued that

human sacrifice in Mexico actually did little more than change the location of the violence

of war.

While a European battle at any point in history might see tens of thousands of soldiers killed,

all the violence usually took place out of sight of most of the population.

Meanwhile, an Aztec battle would see relatively few casualties, but all the killing would

be done where everyone in the city could see it.

I think everyone should make up their own minds on how they feel about this.

We shouldn t try to minimize the day-to-day horror that this practice would have involved,

but it s also important to remember that sacrifice is not something that makes the Aztecs particularly

exceptional when looked at in a wider historical perspective.

An even more difficult question to answer is how the average Mexica person of the time

felt about it all.

It s likely that reactions to the practice were extremely varied and complex.

Many ordinary people may have viewed it with a mixture of fear and fascination, as European

peasants once felt about our own grisly, drawn-out public executions.

Or perhaps they felt about it the way we feel about the more than a million people who die

around the world in car accidents each year.

A tragedy for the individuals, they may have thought, but not something that can be helped

if we want the world as we know it to keep on going.

Some certainly may have enjoyed the spectacle.

Like the ritual slaughter of gladiators and unarmed prisoners in the Roman Colosseum,

the Aztec sacrifices would have been raucous and would have reminded anyone who watched

them of the fragility of their own lives, and of the power of the state.

The sight would have served a purpose in terrifying people into obeying their king.

Of course, they would probably have got a guilty rush of pleasure as they thought, I

m glad that s not me up there.

While all of these questions are still a matter for lively debate, one thing is for sure;

the practice of human sacrifice was about to increase sharply.

Part of the reason for that is a dramatic change in the political landscape in the Valley

of Mexico.

As the year 1400 passed by, the world of the valley was about to erupt into war.

One king would soon rise to power in Tenochtitlan who would embody the warlike spirit of the

Mexica like no other.

He would turn this booming island city into the hub of a powerful empire and a military

force that would eventually dominate the whole valley and beyond.

His name was Itzcoatl.

Little is known about the early life of Itzcoatl.

His name meant obsidian serpent and it would prove fitting to his character.

Itzcoatl was a noble in the court of the Mexican King Chimalpopoca.

Chimalpopoca was his nephew and had come to the throne at the age of 20.

This young king had a kind heart, but he lacked a certain degree of strength and experience.

At this time, the Tepanec people still ruled the Valley of Mexico and Tenochtitlan, like

the rest of the valley, was under their thumb, and for good reason.

The Tepanecs had a powerful army supplied with fighting men by over 40 cities.

Their capital city of Azcapotzalco controlled the shore of the lake right where the three

great causeways of Tenochtitlan met the land.

Any time the aqueduct broke, its people needed the Tepanecs' permission to bring in new materials

to rebuild it.

So, Tenochtitlan didn t cause any trouble.

They paid a regular tribute to the Tepanecs and agreed to send soldiers to fight in their

wars.

Part of why the Tepanecs had been so successful in the last century was down to the astonishingly

long reign of their current king.

His name was Tezozomoc, and if the Aztec records are correct, then by the year 1420, he was

already over 100 years old.

King Tezozomoc had ruled in Azcapotzalco for over fifty years, as the historian Fernando

Ixtlilxochitl recalls.

He was so old that they carried him about like a child swathed in feathers and soft

skins.

They always took him out into the sun to warm him up, and at night he slept between two

great braziers, and he never withdrew from their glow.

He was very temperate in his eating and drinking and for this reason he lived so long.

But the Tepanecs and their old king were not loved by the other people in the valley.

They ruled with a regime of violence and terror.

King Tezozomoc had a fearsome reputation, as Ixtlilxochitl recalls.

He was the most cruel man who ever lived; proud, warlike, and domineering.

The Tepanecs kept the other cities of the valley in line with a regime of targeted assassinations

and military force.

Any king standing in their way was soon likely to find men sneaking into his palace with

obsidian daggers, ready to cut his throat as he slept.

The invasion of a Tepanec army would usually follow soon after.

When Itzcoatl was just a young lord, he saw one stark example of this in the fate of the

city of Texcoco, which sat on the opposite shore of the lake to Tenochtitlan.

Texcoco was home to a young prince by the name of Nessahualcoyotl who is one of the

most fascinating characters in this story.

Nessahualcoyotl s name meant hungry coyote .

But for most of his early life, he would have lived in the lap of luxury.

That is, until his father, the king of Texcoco, got in the way of the ambitions of the Tepanec

Empire.

When Nessahualcoyotl was 15 years old, Tepanec assassins burst into his palace and murdered

his father.

Nessahualcoyotl hid from the assassins in the branches of a nearby tree and saw his

father s death right before his eyes.

When it was safe to come down, he fled the city.

A Tepanec army soon marched on Texcoco.

The Tepanecs demanded that the weak young king of Tenochtitlan, Chimalpapoca, also send

troops to help in their war.

So, the armies of Tenochtitlan helped the Tepanecs to burn down the city.

The young prince Nessahualcoyotl, still grieving for his father and his slaughtered people,

was forced to flee the only place he had ever called home.

For four years, Nessahualcoyotl hid in the mountains disguised as a commoner.

He must have been terrified that assassins would find him and that he would soon meet

the same fate as his father.

But Chimalpopoca, the young king of Tenochtitlan, seems to have felt a pang of regret about

the part that he played in the destruction of Texcoco.

He travelled to the Tepanec capital to meet the old King Tezozomoc, and intervene on the

young prince s behalf.

I think it s an incredible image.

King Chimalpopoca, a young man of twenty, entering the dim-lit chamber.

The ancient King Tezozomoc, swaddled in his feathers and skins, sitting beside his burning

brazier for warmth.

We can imagine Chimalpopoca s voice shaking a little as he asked this powerful emperor

to spare the Prince Nessahualcoyotl.

He asked that the prince be allowed to come to Tenochtitlan to live in peace and to study

at one of the city s schools.

Amazingly, King Tezozomoc agreed to the proposal.

So, the young Nessahualcoyotl was allowed to come down from his exile in the mountains

and to live in Tenochtitlan.

He studied in a kind of school called a Calmecac, where the children of the nobility learned

the crafts of high society, how to become military leaders, administrators, and priests.

It must have been a strange feeling for the young prince; to live just across the lake

from the home that had been taken from him, and where a puppet king now ruled.

He would even have been able to see his home of Texcoco across the lake on a clear day.

He may have sat at the tops of the tall pyramids, gazed out over the lake, and wondered if he

would ever be able to return home.

He spent ten years in Tenochtitlan and he would always have an affinity for the city

and its culture.

It's here that he met the noble Itzcoatl, the obsidian serpent.

We don't know exactly when they met, but I like to think it may have been during this

time.

Perhaps they wandered the markets of Tlatelolco, watched the canoes coming in with sheathes

of maize, and ate fish-egg tortillas together.

They may have walked around the great plaza of Teopan and spoken about their shared hatred

for their Tepanec rulers.

Perhaps it s here that they began to hatch their plan to wrest control of the valley

away from the cruel king Tezozomoc.

They couldn t have known it then, but the chance they were hoping for was just around

the corner.

The reign of King Tezozomoc had been a golden age for the Tepanecs.

But in the year 1426, the old king finally died at the grand age of 106.

Suddenly, the power of the Tepanec Empire began to falter.

Tezozomoc had a great number of sons.

Upon his death, one son named Tayatzin took the Tepanec throne.

But one of his brothers, a man called Maxtla, fancied his chances.

Maxtla toppled his brother from the throne and seized the crown for himself.

A full-blown succession crisis erupted, and civil war broke out across the Tepanec lands.

Suddenly, the city of Tenochtitlan found itself right at the centre of it.

The kindly young King Chimalpapoca had a strong sense of fairness.

He backed what he saw as the rightful king, but the usurper Maxtla was of course enraged.

He began to exchange insults with the Chimalpopoca, and at one point even sent him a gift of women

s clothing.

Chimalpopoca was by this time around 30 years old, but he still had that strain of youthful

naivety.

In the year 1427, he was lying asleep in his palace when a band of trained killers crept

over its walls.

They snuck into the bedchamber of King Chimalpopoca and killed him.

The Tepanec usurper King Maztla must have been delighted when he heard the news, but

he didn t realise that he had scored something of an own-goal.

The death of the kindly King Chimalpopoca made way for another, much stronger king to

rise in Tenochtitlan.

Now was the turn of Itzcoatl, and he would spell the end of the Tepanec Empire.

Itzcoatl partnered with the exiled prince Nessahualcoyotl, and together the two of them

went from city to city around the valley, gathering people to their cause.

Everywhere they went, they found people who had had enough of the Tepanecs' rule.

The Aztec chronicles record that they gathered an army of up to 100,000 men.

When the Tepanecs most loyal ally, the city of Tlacopan, joined the war on Itzcoatl s

side, King Maxtla must have known that his days were numbered.

But he didn't give up without a fight.

The war raged on for two years.

At first, the Tepanecs besieged Tenochtitlan.

They knew that if they could take out the island city early on, the resistance to them

would be destroyed.

But the lake city was exceptionally well-placed to withstand a siege.

A steady stream of goods and reinforcements would have easily passed in and out of the

city by canoe.

Tenochtitlan held out until King Itzcoatl arrived with his army and sent the besieging

Tepanecs packing.

Their retreat quickly turned into a rout, and the combined forces of Itzcoatl and Nessahualcoyotl

marched on the Tepanec capital of Azcapotzalco in the year 1428.

They encircled it, broke down its walls, and burned it to the ground.

The usurper King Maxtla was dragged back to the city of Tenochtitlan and killed at the

top of its great temple.

The era of Tepanec rule was over, and now a new power ruled in the valley.

Prince Nessahualcoyotl returned to his home of Texcoco, and ruled as its king ten years

after he had fled as a frightened child.

Itzcoatl also ruled in Tenochtitlan.

Together with the smaller partner of Tlacopan, they formalized a treaty that would see them

rule over the Valley of Mexico together.

These three cities divided up the former Tepanec lands, and their kings agreed to cooperate

in future wars of conquest, dividing the tribute between them.

This was a treaty known as the Triple Alliance, and it would form the foundations of a true

empire in the region, a power that would one day come to be known as the Aztec Empire.

Writing in the 1840s, the historian W.H. Prescott wrote that he believed there were two sides

to the Aztec character, and he thought these two sides actually came from different sources.

Their high-minded and austere culture, their refined etiquette, mathematical skills, and

love of poetry must have been inherited from the refined ancient empire of the Toltecs,

he wrote.

But the other side of their character was also there; the side of blood sacrifice, the

side that relished the thrill of battle and conquest.

He suggested that this came from their nomadic tribal beginnings.

This theory is pretty simplistic and impossible to prove, but it does show you how much the

two conflicting sides of the Aztecs have puzzled historians for almost as long as they have

been studied.

During this period, these two sides were embodied in the characters of the two kings Itzcoatl

and Nessahualcoyotl.

When Nessahualcoyotl returned to rule in Texcoco, he was a fair and relatively peaceful king.

He built a temple there where he banned the practice of human sacrifice and even the sacrifice

of animals.

He was also a lover of literature.

He built a great library in Texcoco, gathering together all the manuscripts that he could;

ornately painted documents written in pictographs on deer skin and bark paper.

He even wrote poetry himself which was passed down by word of mouth before being written

down by the Spanish in the 16th century.

This extract from one of his more famous songs shows that Nessahualcoyotl believed that poetry

helped to soothe the pain of living.

Perhaps my friends will be lost, my companions will vanish

when I lie down in that place.

Flowers are our only garments, only songs make our pain subside.

But his partner-king Itzcoatl was different.

He had the ambition of establishing this new Triple Alliance as an imperial power to surpass

anything the Tepanecs had achieved, and he was happy to use any ruthless methods to do

it.

Helping him in this task was a shadowy figure known only to history as Tlacaelel.

Tlacaelel had been the brother of the kindly King Chimalpopoca, killed in his bed by Tepanec

assassins.

But he had none of Chimalpopoca s softness.

Throughout the war with the Tepanecs, he had acted as an advisor to Itzcoatl, and rose

through the ranks of the royal court to become his chief advisor.

He would hold this position through the reign of three subsequent kings, and some have claimed

that throughout this time, Tlacaelel was the true ruler of the Aztec Empire.

Although he was offered the crown multiple times, he always refused it, preferring to

remain in the shadows, the power behind the throne.

On one hand, Tlacaelel was a dedicated reformer.

He was determined to turn the Aztec state into an efficient machine, improving and modernizing

its administration and methods for collecting taxes.

But the kind of state that Tlacaelel wanted to build also had some remarkable and terrifying

similarities to dictatorships that we might recognize from our more recent history.

First of all, Tlacaelel understood the importance of controlling information.

As soon as Itzcoatl took the throne in Tenochtitlan, Tlacaelel advised him to order an inspection

of its library and to destroy any historical texts that they found inconvenient to their

narrative.

This act is remembered in the Aztec Chronicles.

Once they used to keep a record of their history, but it was burned at the time when Itzcoatl

reigned in Mexico.

It was agreed, and the nobles of Mexico said, It is not fitting that all the people should

know the paintings.

The common serfs will be led astray and the earth will be made crooked because in the

documents are many lies, and many heroes have been taken for gods.

Here the division between the two sides of the Aztec character couldn t be more pronounced.

On one side of the lake, King Nessahualcoyotl was writing poetry and building a library,

while on the other, Itzcoatl was burning books in bonfires.

While Nessahualcoyotl had banned human sacrifice, King Itzcoatl would preside over a massive

increase in the practice.

Once again, the advisor Tlacaelel seems to be behind it.

I think Tlacaelel understood all too well the power of the violent public spectacle

as a means for controlling the masses.

I think he wanted the people of the valley to truly fear the power of their state, and

fear it they did.

Alongside an increase in public brutality, Tlacaelel also reformed the religion of the

valley.

The Mexica war god Huitzilapotchtli had before been one among several gods like Tlaloc and

Quetzalcoatl.

But he would now be raised to rule over all the others, elevating the Mexica to the status

of God's chosen people.

The power of the military was now paramount in Aztec society.

Tlacaelel claimed that only warriors who died in battle would go to serve Huitzilopochtli

in the afterlife.

This was a new age of militarism in which the warriors who died in battle were honoured

as the supreme heroes.

One hymn, meant to be sung by all the people of Tenochtitlan, embodies the new warlike

spirit of this age.

The bonfire smokes!

Shields thunder!

God of the ringing bells!

The flower of the enemy shudders!

Eagles and tigers resound!

The dust grows yellow.

Red blossoms shall bud, unfold, and open into flower.

O God Eagle, in your house you rule.

Your banner trembles and flames, and the bonfire crackles!

Partly due to this new militaristic attitude, the Aztec Empire expanded with unstoppable

speed.

King Itzcoatl gathered a great army and marched on his neighbouring cities, conquering them

one by one.

At one point, Diego Duran writes that Tlacaelel gave this proclamation to the lords of the

gathered cities.

We are capable of conquering the entire world.

For a time, that s what it must have looked like.

Soon, all the other cities around Lake Texcoco were subdued.

Other states, alarmed by the rapid expansion of the Aztecs, gave in to all their demands

without a fight, and paid regular tribute.

Soon, the Aztecs began to send their armies out beyond the valley, marching through the

mountain passes cut between the volcanoes.

When the King Itzcoatl died in 1440, a new king, Moctezuma the First, rose to power.

He reformed the Aztec Empire and massively expanded it, turning Tenochtitlan into the

dominant party in the former Triple Alliance.

The war over the Aztec character was being won, and it was the warlike, domineering side

of Tenochtitlan that was coming out on top.

When Moctezuma the First died, he was followed by the Kings Axayacatl and Tizoc who both

expanded the empire even further.

All these kings had the same shadowy figure Tlacaelel advising them.

Aztec armies marched into the lands to the north, bringing the desert peoples under their

rule.

They marched south and made inroads into the land of the Maya and on to the Pacific coast,

and they went east and conquered lands on the Atlantic coast, too.

Tenochtitlan was never an empire in the way we might imagine it.

It usually didn t occupy the lands it conquered, and it rarely set up garrisons or installed

administrators, except in the most rebellious provinces.

It was more like a network of tribute which saw wealth flow in one direction; to the city

of Tenochtitlan.

The historian Inga Clendinnen describes it in the following manner.

Tenochtitlan was a beautiful parasite, feeding on the lives and labour of other peoples and

casting its shadow over all of their arrangements.

The administration of the empire was conducted along a remarkable communications network

made up of well-maintained roads heading to every town and village.

There were no horses in the Americas, so messages were carried by runners stationed every 4km

or so along the roads.

Each messenger would run those 4km, and then pass on the message to the next runner.

In this way, messages could pass the whole length of the empire in only a matter of days.

But the Aztecs didn t rule with kindness.

In the villages they conquered, their soldiers and tax collectors were hated.

They took the peoples' food and goods in taxation, took their people for sacrifice, and brutally

put down any resistance.

There was one people who the Aztecs treated with an unmatched level of cruelty.

These were called the Tlaxcalans, a people who spoke Nahuatl and who lived just over

the mountains to the east of the Valley of Mexico.

If you listen to the Tlaxcalans, they would tell you that the Aztecs had tried and failed

many times to conquer them.

But the Aztecs would claim that they could have conquered them at any time and simply

chose not to.

Either way, a strange kind of situation developed.

The Tlaxcalans remained independent, but they were at a constant state of war with the Aztec

Empire.

The Aztecs surrounded and blockaded them, stopping any luxury goods such as salt or

fine textiles entering their lands.

The Tlaxcalans were also forced to compete each year in an event known as the flower

wars.

The name "flower war" is a curious pairing of words.

The Nahuatl language is particularly fond of these kind of pairs.

In English we do this too; we talk about our bread and butter, our heart and soul, or sticks

and stones.

These are pairs of words that together mean something else, and this was a big feature

of Nahuatl.

If they wanted to say that someone gave a speech, the Mexica would say he gave his word

and breath .

They described your village as your water and hill .

When someone died, they passed into cold and silence .

If you did something in secret, you were doing it in clouds and mist .

Their word for poetry was flower and song .

In Nahuatl, flower meant "poetic and beautiful".

In Aztec poems, warriors are often said to die what they call a flowery death ; that

is, a noble, poetic death.

If a warrior died in battle, they were believed to be resurrected among what the Aztecs called

flower and bird ; that is, they may become part of the natural world around them, as

this piece of Aztec oral poetry suggests.

Bells clamour, the chief is resplendent, he who makes the world live is full of delight.

The flowers of the shield are opening their petals;

glory spreads, it revolves around the earth.

Here is the intoxication of death in the midst of the plain!

There, as war breaks out on the plain, the chieftain shines, spins, gyrates

with flowery death in war.

Fear not, my heart.

On the plain I covet death by the obsidian knife.

All that our hearts desire is death!

The flower wars were were highly theatrical and would have looked something like a Mardi

Gras parade.

The Mexica war bands dressed in their most extravagant and brightly coloured clothes,

the jaguar warriors in their mottled skins, the eagle warriors in their bright feathers,

all carrying brightly coloured shields hung with feathers and embroidered with heraldic

symbols, the flapping of orange cloaks and red hats, some wearing masks, tassles, and

jangling bells.

But all this color shouldn t fool you.

The stakes in the flower wars were still very real.

Warriors would have carried spears, obsidian daggers, and a weapon known as a macuahuitl,

roughly equivalent to a sword.

These looked something like a cricket bat, but with the edge ringed with shards of obsidian

glass.

As with most Aztec warfare, the point wasn t to kill, but to capture prisoners for sacrifice.

After a flower war, the skulls executed prisoners were displayed as grisly trophies on enormous

racks in the city of Tenochtitlan, some of which have been uncovered by archaeology.

The largest ever found was discovered at the main temple, and contained over 650 skulls.

The Tlaxcalans led a pretty miserable existence.

They were starved and impoverished, and forced to participate in this ritual slaughter of

their citizens.

Unsurprisingly, this gave them a bitter hatred for the Aztecs.

This, ultimately, is where the seeds of the whole empire s collapse would be sown.

The Aztecs had risen to power in the first place because the Tepanec Empire was so hated

around the valley.

The Tepanecs cruel regime meant that in the end, no one was willing to fight alongside

them, and their allies were easily convinced to turn against them.

History would later show that the Aztecs should have learned this lesson.

When the shadowy advisor Tlacaelel passed away peacefully at the age of 90, he died

a happy man.

The year was 1487.

The island city of Tenochtitlan was now the beating heart of an empire that stretched

from the Atlantic to the Pacific Ocean.

It governed the lives of as many as 6 million people and was on course to become the greatest

empire that the continent had ever seen.

But in little over thirty years, this whole society would come crashing down.

That s because they would soon encounter another power that would outmatch them in military

force, in ruthlessness, and at times, in cruelty.

Only thirty or so years after the death of Tlacaelel, the chronicles in the Florentine

Codex record that once again over Mexico, a mysterious light appeared in the sky.

It was a comet of dazzling brilliance.

As the days went on, it grew brighter.

Ten years before the arrival of the Spaniards, an omen first appeared in the sky like a flame

or tongue of fire, like the light of dawn.

It appeared to be throwing off sparks and seemed to pierce the sky.

It was wide at the bottom and narrow at the top.

It looked as though it reached the very middle of the sky, its very heart and center.

It showed itself off to the east.

When it came out at midnight, it appeared like the dawn.

Although no one could have guessed it, this light in the sky was a harbinger of the end

of the Aztec age.

As we saw earlier, during the low sea levels of the last Ice Age, a land bridge existed

from Asia that stone age humans used to cross into the Americas.

But as sea levels rose from about 16,000 years ago, that bridge was swallowed up by the waves.

Humanity was now separated into two vast populations, one on each of the world s two great landmasses.

Although neither of them knew it, the separation of the continents was the starting pistol

in a race for their very survival.

At some point in the future, these two populations would meet.

The developments they made during the intervening 16,000 years would determine which of them

would survive that encounter.

For a number of reasons, the people who settled in the smaller landmass, the continents of

the Americas, were at an inherent disadvantage.

There are a lot of factors at play here.

This is a hotly contested subject that people feel understandably emotional about.

But for me, the most obvious and first point to make is that the people of the Americas

had simply arrived in their lands later than other humans.

We evolved as a species in Africa between 300-200,000 years ago, and in the last 60,000

years began to migrate out of Africa and on to the rest of the world.

We reached Southern Asia by about 50,000 years ago, China by 40,000 years ago, and most of

Europe by 30,000 years ago.

This means that humans had already settled in virtually the whole Afro-Eurasian landmass

for tens of thousands of years before they ever set foot in the Americas.

All that time, they spent growing their populations and steadily making the incredibly slow transition

from hunter-gatherers to part-time farmers, and then from part-time to full-time farmers.

Their settlements grew until the early cradles of civilization like the Indus Valley, Egypt,

and Mesopotamia burst into the light of history around 7,000 years ago.

As we saw in the last episode, a cradle of civilization takes a long time to form.

Part of the reason for this is that virtually every food we eat today didn t exist until

we came along and created it.

Far from the bountiful Garden of Eden, the earth originally didn t provide that much

to eat for its human inhabitants.

What little there was would have tasted pretty bad.

From wheat and barley to bananas, peas, and oranges, each delicious food we know today

began as an ancestor that was much more unpalatable, much less nutritious, and much more difficult

to digest.

The banana is just one of countless examples.

It began in Southeast Asia as an unrecognizable wild species with bluish-green skin and many

large, hard seeds.

They're virtually inedible to humans but over millennia, desperate hunter gatherers would

have picked the ones that were most bearable to eat, and taken them home.

The seeds from these would have grown near to their settlements, and later, these early

humans would begin to cultivate them in a more purposeful way, picking only the juiciest

of their new crop to create the next generation.

Incredibly slowly, so slowly that no one would have noticed the difference over their lifetime,

the plant began to change.

Its seeds got smaller, its flesh got sweeter and creamier, and its skin turned that deep

yellow we all recognize today.

We owe so much to the work of those thousands of nameless generations who tirelessly domesticated

these plants.

It took many thousands of years for the people of Mesopotamia to change wild mountain grasses

into the nutritious wheat and barley that we know today.

This process began as early as 10,000 BC.

From there, these cereals spread to the rest of Afro-Eurasia.

Peas and pulses like lentils were another of the earliest domesticated crops.

Wild peas were even eaten by Neanderthals, as the 46,000-year-old remains from the Shanidar

cave in Kurdistan seem to show.

But modern peas were first domesticated in Iraq as early as 11,000 years ago.

This was nothing short of an agricultural revolution that fueled the growth of early

societies.

As the quality of these foods improved, they offered greater nutrition to our diets, higher

calories, and more protein, and it became possible to support larger populations.

But the people of the Americas were much newer to their lands.

The earliest people to ever live in the Valley of Mexico would have only just arrived around

the year 12,000 BC, about the time that peas and wheat were already beginning to be cultivated

in Mesopotamia.

These earliest Mexicans found huge herds of mammoths and other animals that could be hunted.

It would have been several millennia before they began to feel the pressure to move away

from their hunter-gatherer lifestyles.

Due to this, one of the most common foodstuffs in the Americas, maize or corn, only began

to be domesticated around seven thousand years ago.

At this time, the Ubaid culture in Mesopotamia was already a thriving agricultural society

as we saw in the previous episode.

This meant that in the long, arduous work of domesticating crops, the people of the

old world had something like a three or four millennia headstart.

Some have suggested that the nature of the plants themselves may have also been a factor.

Once again, the people of the Americas suffered a stroke of bad luck.

One of the most common foodstuffs in Mexico was corn which likely descended from a plant

called Teosinte.

This is an incredibly bitter kind of grass.

It looks nothing like the rich, yellow globes of corn we know today.

Since such a drastic change had to be bred into this unappetizing plant, it may haven

taken longer for early people in the Americas to domesticate it than for the people in Mesopotamia

to turn wild grass into wheat, or wild peas into lentils neither of which require such

a dramatic transformation.

There are other factors, too.

In the Americas, a lower diversity of animals also acted as a disadvantage.

There were only two animals in the Aztec world that could be domesticated; turkeys and dogs.

But in the old world, livestock like sheep, goats, and pigs contributed greatly to the

amount of protein available to the population.

Cows were a rich source of meat and milk, and could also be used as pack animals to

carry loads and pull ploughs.

But above all, there was the horse.

Although the horse had evolved in the Americas, it had been extinct there since the last Ice

Age.

It s sometimes said that the indigenous American empires like the Aztecs never invented the

wheel, but that s not actually true.

We ve found numerous examples of clay toys made for Mexica children which include perfectly

engineered wheels.

But if the Aztecs ever experimented with wheels for larger vehicles, it s likely they would

have quickly given up on the idea.

Without any horses or oxen to pull a cart, the design of the wheel wouldn t have saved

much labour.

The Aztecs simply carried things from place to place using straps that attached to their

forehead.

This worked well enough for them, but it tied a large proportion of the population down

in manual labour.

Compared to the horse-driven power of the old world, it was just another setback.

The Afro-Eurasian landmass is just about exactly twice the size of the combined continents

of the Americas.

This larger habitable area, along with the extra tens of thousands of years that people

had lived there, meant that the population in the old world was much higher.

Estimates for the population of the Americas pre-contact vary wildly.

Some historians have gone as low as 8 million while others have gone as high as over a hundred

million.

But I find an estimate of about 60 million to be reasonable.

But compared to the old world, the difference is stark.

By contrast, China alone had surpassed 140 million by the year 1200, a century before

the Aztecs had even arrived in the Valley of Mexico.

This larger population meant simply that there were more human brains put to work on the

business of inventing new things.

Vast trade networks like the Silk Road meant that if something was invented in China or

India, it would only be a matter of years before it would be available in Europe.

Due to their three or four millennia headstart in domesticating crops and all these other

advantages, the timelines of the two sides of the world show a marked difference.

While the people of Mesopotamia developed pottery over 7,000 years ago, the first pottery

in Mexico would not begin for another two and a half thousand years.

While bronze-making began in India and the Near East around 3,300 BC and spread to Europe

and East Asia in the following centuries, experimentation with bronzework was only just

getting started in Mexico when Tenochtitlan was at its height in the 14th century.

High-carbon steel was invented in South India in the 6th century BC and exported around

the old world.

It would never be invented in the Americas.

By the 5th century AD, Mexico s first Empire of Teotihucan had only just reached its height,

but the old world had already seen millennia pass that saw the rise and fall of the Sumerian,

Egyptian, Assyrian, Babylonian, Persian, Greek, and Roman Empires.

When Teotihuacan fell around the year 550, China s Chen Dynasty had invented matches,

and Indian engineers had invented the spinning wheel.

When the Toltec Empire fell in the Valley of Mexico around the beginning of the 12th

century, the Chinese had already invented gunpowder and a magnetic compass for use at

sea.

When the Mexica people arrived in the Valley of Mexico around the year 1,300 AD, Arab and

European scientists had already described rules for the refraction of light, and Italian

craftsmen had invented the first eyeglasses.

By the time the Aztec Emperors Itzcoatl and Nessahualcoyotl were born, the first handheld

cannons had been invented in China, and naval artillery had been used for the first time

in Korea.

While the poet Nessahualcoyotl built his personal library in Texcoco and Itzcoatl burned the

books of Tenochtitlan, the printing press was invented in Germany.

In the middle of the 15th century, the arquebus, an early form of musket, was developed in

Spain.

All the people of the Americas were incredibly ingenious and inventive, and the Aztecs were

no exception.

But they could never make up that three or four millennia headstart.

The race that would determine the outcome of the coming war of the worlds had always

been rigged against them.

One technology above all others would prove to be the decisive factor in the coming collision

of worlds.

That would be the ocean-going ship.

In the 14th to 15th centuries, developments in naval technology gave rise to a new kind

of vessel known as the caravel.

Until then, Europeans had been restricted to only navigating around the coasts.

But Portuguese craftsmen were soon able to develop larger and more powerful ships.

Caravels allowed them to explore along the coast of Africa.

By the end of the 1400s, these had been upgraded to the much larger and more powerful carracks.

These were large, durable ships with as many as six sails, well-suited for long ocean-going

voyages.

They also weighed well over a thousand tons, large enough to carry huge amounts of supplies,

suitable for voyages of many months.

The carrack meant that regular voyages could now take place between Europe and India, all

around the coast of Africa, and even on to China.

While the Silk Road cities like Baghdad, Tashkent, and Samarkand had once been the hubs of the

world s trade, those centres began to move to Europe along these newly-opened trade routes.

European cities swelled with incoming wealth, and in the final decades of the 15th centuries,

the European countries that looked out over the Atlantic Ocean began to wonder if they

could make even more ambitious voyages.

In the year 1492, only five years after the death of that shadowy advisor Tlacaelel in

Tenochtitlan, a carrack called the Santa Maria was sailing across the Atlantic Ocean, accompanied

by two smaller caravels.

On board was the explorer Christopher Colombus.

The Aztecs knew no more about those three ships than the enormous Pterodactyl Quetzalcoatlus

knew about the asteroid that had once sped steadily towards the Gulf of Mexico.

But as a light once again appeared in the sky over Central America, that blazing, blood-red

comet, a new threat just as deadly was speeding their way, one that would take them completely

by surprise and change their world forever.