Meat, Gods and Aztec Economics

Would you like to know exactly how Aztec sacrifice worked?

Are you sure?

All jokes aside, if you're squeamish you probably shouldn't read this post, because you won't thank me. But if you have the stomach for it, it's actually a pretty interesting topic, and some basic Googling led me to some places I didn't expect. Most of all, though, I was genuinely shocked at how fast and easy the whole process was.

Those stairs probably didn't stay white.

Some time around 1521, the last victim was taken to Tenochtitlán to be sacrificed at the summit of Templo Mayor. At the time, Tenochtitlán was the biggest city in the world, with some 300,000 inhabitants, twice the size of contemporary London. Built on a low island and reclaimed land in the midst of the shallow Lake Texcoco, it had canal streets like Venice, a system of aqueducts (even without the pollution of a whole city, Lake Texcoco was filled by runoff from the mountains, too saline to drink), barber shops, parks (the Aztecs had a passion for flowers) and even a zoo. It was linked to the shores by stone causeways, each with three gaps that allowed canoe traffic to pass through while doubling as drawbridges in case of invasion. And yet the centrepiece of the city was Templo Mayor, a human abbatoir dedicated to the ritual slaughter of prisoners captured in war. As unimaginable as it might be to us, it's quite possible the last victim was consenting, as there are plenty of surviving tales of particularly impressive prisoners being offered their freedom, but preferring to be sacrificed instead, lest they offend whichever god ordained their deaths. With the Aztec power base shaken after La Nocte Triste, it's possible this was the only kind of prisoner they could take.

On the other hand, of course, with their "empire" boiling over the Aztecs would've had no problem finding battles to fight and prisoners to take, so it's equally possible the last sacrifice had to be dragged to the altar by his hair. Either way, for the last time four priests grabbed some poor bastard by the arms and legs and held him over the sacrificial pillar – usually depicted like a mortician's slab, but actually more like a stone-age version of the bollards they use to prevent ram raids (hell on your back, but for obvious reasons the victim's comfort wasn't a concern). And then the priest cut him open with an obsidian blade, removed his heart, and completed the necessary rituals to honour his god, Huitzilopochtli ("Weet-zee-lo-potch-tlee"). Templo Mayor felt its final splash of human blood. Then, Cortés returned and began the Siege of Tenochtitlán, and the end had come. It was the year of One Reed, and the setting of the Fifth Sun.

A Weird & Bloody Religion
"Templo Mayor" just means "Great Temple" in Spanish, which might be parochial as hell, but it's still more accurate than the usual description of Templo Mayor as a pyramid (the Aztecs called it huei teocalli, which means... Great Temple. God-House, technically). Let's be clear the Mesoamerican temples were not pyramids, a Greek word derived from pyramis, "a kind of cake made of roasted wheat grains preserved in honey," which had that characteristic shape. The name was given by Alexander the Great's soldiers, who refused to be impressed by what the Egyptians had accomplished. Upon being shown the greatest feat of architecture in the world, the Greeks dismissed it as a little bun.

No royal tomb, however, Templo Mayor had a completely different function in public life, much closer to the Roman temples that were built on plinths so the public could view the rites for themselves. It was a stage for politico-religious theatre, and the relative height of the temple gives a clue as to how big a crowd would've gathered to watch. It was dedicated to two gods, the aforementioned Huitzilopochtli, the patron deity of the Mexica tribe, and the rain god Tlaloc.

Tlaloc – the Giver, the Green One, God of the North and Lord of Seasons and Weather – isn't hard to comprehend: he's a god of farmers, and having grown up around farmers I completely understand why he was such a big deal. If you somehow convinced the farmers from my hometown that human sacrifice would guarantee them good rain, they'd be all for it, no question. Having the your whole life dependent on the fickle whim of nature will do that to a man. Like most Mesoamerican gods Tlaloc demanded human sacrifice, but being a water god his victims were usually drowned, and they were usually children. For whatever the hell it's worth, a famous palace painting known as The Paradise of Tlaloc shows the afterlife of those slain by drowning, their souls taken care of by Tlaloc, their depictions bright, happy and playing children's games. In the end, though, he's just a god of farming, and not especially interesting.

Relatively.

Huitzilopochtli, the Midday Sun, the Eagle, the Hummingbird, God of the South, is much harder to wrap your head around because he's buried under a lot more cultural metaphor. His nagual, or animal disguise, was the eagle, and it was in the form of an eagle that he showed the Aztecs where they should build their city by alighting on a nopal cactus with a snake in his beak – an image that remains on the Mexican flag today. He was born fully armed and ready for war, wielding his weapon xiuhcoatl, the Turquoise Serpent (i.e. lightning), and his very first act was to slaughter without mercy his rebellious sister Coyolxauhqui and his 400 siblings, their dismembered bodies becoming the moon and stars.

His name is usually translated "Left-Handed Hummingbird," which only adds to the confusion. He's also called a war god, but that's also problematic, because "war" is just what we call it, and the word carries a lot of Western baggage – mainly the assumption that it's political (Clauswitz's postulate that "War continuation of politics by other means," continues to haunt us, because it's one of the most misquoted lines outside of Scripture). The operations of the Aztec warriors were much more bound up with their religion: the Emperor, or tlatoani, was himself a priest of the state religion and often wielded the knife himself. One of the elite divisions of the Aztec army were the Eagle Warriors (cuauhmeh), who dressed for battle in feathered suits complete with talons and a beaked helmet – in other words, they dressed up as Huitzilopochtli. They were very careful not to kill on the battlefield, which was considered clumsy; instead, they did their utmost to bring prisoners back for sacrifice, and their ascent through the ranks was based on how many prisoners they'd taken. A boy who'd taken his first prisoner was a tlamanih, or captor, and was now considered a man. Two, and he was a cuextecatl; three, a papalotl, or butterfly. The ranks climbed higher and higher as prisoners accumulated, until he might achieve the elite rank of ocelotl, or Jaguar Warrior, for capturing twelve in two consecutive battles. Aztec "warfare" then can be seen as a function of, and an expression of, the Aztec religion.

So who was this Huitzilopochtli, the engine behind it all? The first clue is that to translate his name as Left-Handed Hummingbird is apparently to get it exactly backwards. In Classical Náhuatl ("Nah-wat," the language of the Aztecs), huitzilin, or "hummingbird," is the modifier for opochtli, the "left-hand side." So... Hummingbirded Left-Side? That doesn't seem to make a great deal more sense, until you realise the Aztecs believed that dead warriors were reincarnated as hummingbirds, and they considered South to be the left side of the world. So, metaphorically, his name conveyed something more like, "Resurrected Warrior of the South." In other words, he's a god of dulce et decorum est, of military necrophilia, of what Zack Snyder's Spartans called, "a beautiful death." Young Aztec males wanted nothing better than to die gloriously in battle (or on the altar) to return as hummingbirds. In Náhuatl they sang:

There is nothing like death in war,
nothing like the flowery death
so precious to Him who gives life:
far off I see it: my heart yearns for it!

Certainly a commoner working in the fields could expect no such pleasant afterlife, and if you consider gods to be reflections of the people who imagine them, as I do, then that's a big clue to the Aztec national character.

Like Baldr, like Osiris, like Demeter, like Jesus Christ, Huitzilopochtli was also a dying-and-rising god. He died every evening and had to be given the nourishment (tlaxcaltiiliztli) to fight off his moon-and-star siblings and rise again in the morning. To that end he demanded blood, the fiery hot blood of courageous warriors. And as his chosen people, it was up to the Aztecs to give it to him, sacrificing about 15,000 warriors a year on his altars – more than 40 a day. According to the conquistador Bernal Diaz, the resulting skull racks in Tenochtitlán were something to behold.

The poles were separated from each other by a little less than a vara [roughly a yard], and were crowded with cross sticks from top to bottom, and on each cross stick were five skulls impaled through the temples: and the writer and a certain Gonzalo de Umbría, counted the cross sticks and multiplying by five heads per cross stick from pole to pole, as I said, we found that there were 136 thousand heads.

To a culture built on human sacrifice the sight of thousands of skulls was a source of inspiration, not dread. And they must've gained a lot of inspiration from the grand opening of Templo Mayor in 1487, when four lines of prisoners stretching back two miles were slaughtered by teams of priests working in shifts. The precise number of deaths is unknown, but they range from a modest 4,000 to the Aztecs's claimed 80,400. The reality was probably somewhere in between: "Allotting two minutes per sacrifice," says our source above, "the demographer and historian Sherburne Cook estimated that the number of victims associated with that single event was 14,100."

The precise ritual of sacrifice was peculiar to Huitzilopochtli: the victim was slashed open, his heart was torn out, and then the body was sent tumbling down the stairs. Some postulate this was something of a re-enactment, Templo Mayor representing the Hill of Coatepec where Huitzilopochtli was born and slew his sister Coyolxauhqui, tossing her body down the hill. Re-enacting the Sun's defeat of the Moon to give the Sun power to rise again makes intuituve sense to me, though of course I'm no expert. Allegedly the heart was then placed in a brazier and burnt as an offering, but I have serious questions about that as well, because the human heart is supposed to be notoriously difficult to burn. Urban legend? I'm all ears if anyone knows for sure.

Some had questions about whether the priests could actually get the job done in the required two minutes, so joy of joys, Dr Brendan Coventry of the Royal Adelaide Hospital decided to do some experimenting himself (what did I tell you about South Australians?). The results were astounding. Giving himself 20 seconds to get in and remove the heart, he was at first unsuccessful at sawing through the breastplate, because it's all bones. But by cutting through the sternum and diaphragm instead, on his first attempt he was able to extract the heart in 20 seconds flat. The second time, to prove it wasn't a fluke, he did it in just 17.

Medical Investigator Shiya Ribowsky only added to the squick when he commented:

I think the Aztecs had a terrific understanding of human anatomy. When they decided to sacrifice their victims, they knew it was going to be a lot easier to get into the chest cavity by making a hole in the abdominal wall and getting at the heart, than trying to get through the breastplate, the sternum, and the ribs, which were very difficult to saw through.

The victims were held down by four people and the priest would take a knife, and while the victim was still alive, plunge it right into the abdomen, rip open the abdomen with the knife, and made a hole big enough to get their arm in. They put their arm in, pierced through the diaphragm, pushing their hand up into the chest. And the heart is the only thing in the chest that's gonna be going like this [mimics a heart pumping], you know, beating. If feels different than the surrounding tissue. The average adult human's heart is around the size of a small grapefruit, and pretty much weighs around the same, and has that kind of feel in your hand.

So the priest would reach around until he felt the beating heart, grab onto it and then just pull for all he was worth until he yanked it off its attachments. I have no doubt that the victim felt the priest's hand in his abdomen and the hand ripping through the diaphragm, which was, I'm sure, exquisitely painful. And I have no doubt that the victim felt his heart being ripped from its attachments, but at that time the victim would lose consciousness. The reason is, as the heart was being compromised, blood flow to the brain would stop. The brain just doesn't have the capacity to maintain consciousness without that bloodflow.

Most people think that if you pulled somebody's heart out of their body that it wouldn't still be beating, but in fact it absolutely would. The heart has what's called inherent rhythmicity, meaning that the muscle cells of the heart beat on their own and don't require input from the brain to beat. So if you get a heart out of a human body quickly enough, say within a few seconds, it absolutely will still be beating when you're holding it.

I was rather glad to hear the victims lost consciousness once the heart was removed. I know there are anecdotes of guillotined heads seemingly retaining some awareness, but anecdotes don't mean much to me: no blood pressure = no consciousness, okay? It sounds horrific, and it was, but let's not forget that in Europe at the time traitors were broken on the wheel or hung, drawn and quartered. Given the choice of donating my heart to Huitzilopochtli or being drawn and quartered at the pleasure of the English King, I'd much rather the heart thing.

And for the record, don't imagine an obsidian knife wouldn't be up to the job. Obsidian blades can be so absurdly sharp they're still occasionally used to make scalpels today (though for some reason they're not U.S. FDA approved for use on humans). The crystal lattice means obsidian can be made many times sharper than steel, down to 3 nanometres, compared to the 1,000 nanometres (or 1 micron) that is the current definition of "razor sharp." A steel razor presents an edge 10,000 iron atoms thick; in the very best cases, a fresh piece of obsidian can present just one.

Feeding the Masses

Conventional descriptions of the Aztec ritual of sacrifice end with the victim’s body tumbling down the pyramid. Blinded by the image of a still-beating heart held aloft in the hands of the priest, one can easily forget to ask what happened to the body when it came to rest at the bottom of the steps...

This leads to the real surprise of the show: what happened to the dead guy once his heart was gone. The sacrifice scene from Apocalypto up there, being a strange mix of the totally accurate and wildly anachronistic, shows a pitch-perfect Huitzilopochtli sacrifice being carried out by the Mayans (who didn't worship Huitzilopochtli) in the name of Kukulkan (who didn't demand human sacrifice). So it's not such a big deal that it shows the ritual ending with the dude's head being lopped off (unnecessary), and that it later gives us the image of a vast field of dumped bodies to show you what colossal waste of life it all was (with Wally in the middle of it for the cinema release, because Mel Gibson is insane).

But from what I've been reading, there wasn't much waste actually going on. The Aztecs didn't throw the bodies away: they ate them.

After having torn their hearts from them and poured the blood into a gourd vessel, which the master of the slain man himself received, they started the body rolling down the pyramid steps. It came to rest upon a small square below. There some old men, whom they called Quaquacuiltin, laid hold of it and carried it to their tribal temple, where they dismembered it and divided it up in order to eat it...

After they had slain them and torn out their hearts, they took them away gently, rolling them down the steps. When they had reached the bottom, they cut off their heads and inserted a rod though them, and they carried the bodies to the houses which they called calpulli, where they divided them up in order to eat them. – Bernardino de Sahagún

Once the heart had been wrenched out it was offered to the sun and blood sprinkled toward the solar deity. Imitating the descent of the sun in the west the corpse was toppled down the steps of the pyramid. After the sacrifice the warriors celebrated a great feast with much dancing, ceremonial and cannibalism. – Diego Durán

For many years it was assumed the Spaniards made this stuff up to justify the conquest, but recent forensic investigation has confirmed that despite some exaggeration, they were a long way from outright fabrication. Durán in particular deserves your time, because he was writing immediately after the conquest and actually learned Náhuatl, and got into a lot of trouble for allowing the Aztec people to perpetuate aspects of their culture. He has academic cred, in other words, and 500 years later the forensic pathologists are backing him up.

Archaeologist Gabino Lopez Arenas carried out an analysis on craniums, tibia, humerus and jaws located among the offerings of the Great Temple and in the surroundings of the historical centre. The analysis revealed that the individuals had been decapitated and dismembered. It then appears that they were butchered and consumed “to absorb the divine force that held the body of the sacrificed,” said Arenas. “We observed that immediately after the victims were immolated their flesh was removed, this is confirmed because a great quantity of bones had cuts and alterations that were done while the bone was fresh and recently exposed to fire.” – April Holloway, Ancient-Origins.net

The modern perspective on this stuff has been promoted by Michael Harner, whom you can read here; it's a controversial idea, but personally it has me convinced. Not the part about "absorbing the divine force that held the body of the sacrificed", which sounds like bullshit (why to they always assume ancient cultures were fucking Age-of-Aquarius indigo children?). In reality they were after something far more basic: good old-fashioned nutrition.

In the Old World, domestication of herbivorous mammals, such as cattle, sheep, and pigs, proceeded apace with that of food plants. By about 7,200 B.C. in the New World, however, ancient hunters had completely eliminated herbivores suitable for domestication from Mesoamerica. Dogs, such as the Mexican hairless, and wildfowl, such as the turkey, had to be bred for protein. The dog, however, was a far from satisfactory solution because, as a carnivore, it competed with its breeders for animal protein. – Michael Harner, The Enigma of Aztec Sacrifice

In other words, having spent several thousand years getting corn to work, the Aztecs had plenty of calories to go around, but they were starved for animal protein. Eating carnivores is always a last resort for people in this situation, because animals are only about 10% efficient at converting their food to bodymass. To grow a tonne of beef you need to feed your cows 10 tonnes of grass. Eating carnivores adds another layer to that process – lion is apparently completely delicious, but to grow an equivalent tonne of lion meat you need to feed your lions 10 tonnes of beef, which in turn takes 100 tonnes of grass. The loophole here was that dogs are actually omnivorous, so the dogs the Aztecs reared for food were efficiently fattened on vegetables and garbage. Even so, it was a luxury reserved for the rich.

The Aztecs responded to their increasing problems of food supply by intensifying agricultural production with a variety of ingenious techniques, including the reclamation of soil from marsh and lake bottoms in the chinampa, or floating garden, method. Unfortunately, their ingenuity could not correct their lack of a suitable domesticable herbivore that could provide animal protein and fats. Hence, the ecological situation of the Aztecs and their Mesoamerican neighbors was unique among the world's major civilizations. I have recently proposed the theory that large-scale cannibalism, disguised as sacrifice, was the natural consequence of these ecological circumstances.

A principal – and sometimes only – objective of Aztec war expeditions was to capture prisoners for sacrifice. While some might be sacrificed and eaten on the field of battle, most were taken to home communities or to the capital, where they were kept in wooden cages to be fattened until sacrificed by the priests at the temple-pyramids. Most of the sacrifices involved tearing out the heart, offering it to the sun and, with some blood, also to the idols. The corpse was then tumbled down the steps of the pyramid and carried off to be butchered. The head went on the local skull rack, displayed in central plazas alongside the temple-pyramids. At least three of the limbs were the property of the captor if he had seized the prisoner without assistance in battle. Later, at a feast given at the captor's quarters, the central dish was a stew of tomatoes, peppers, and the limbs of his victim. The remaining torso, in Tenochtitlán at least, went to the royal zoo where it was used to feed carnivorous mammals, birds, and snakes.

Through cannibalism, the Aztecs appear to have been attempting to reduce very particular nutritional deficiencies. – Michael Harner

Every month – so at least 18 times a year – the Aztecs would  throw feasts like this, explaining why they tolerated such loose control over their conquests. It's not as mad as you might be thinking. A while ago Cracked ran an article about Steve Callahan, who was shipwrecked and left drifting in a dinghy for two months. The effects on his appetite were... interesting.

My sense of taste also changed, and by that I mean I started to see fish eyes as candy. Obviously I started eating fish. You know, it's not like you're going to run into a cow swimming around out there. But by the end of the voyage I looked forward to the eyes and liver, because they had all sorts of vitamins my body was begging me for, and that made the fish taste so unbelievably good. I ate delicacies you find only in exotic seafood restaurants not because I had to, but because I wanted to. You tell yourself it's gross, but you suddenly want it, because fish meat and water are driving you mad, and also you might be dying of some sort of deficiency... Your body is good at guiding you toward the things that will keep it from croaking, and so suddenly you're hungry for fish eyes. – 5 Things I Learned About Survival While I Was Lost At Sea, Cracked.com

Or delicious long pork, as the case may be, which apparently really does taste like pork or veal. Aztec commoners didn't have regular access to the turkeys and dogs the upper classes were eating; if they wanted animal protein, they had to content themselves with worms or snakes – or this month's prisoners.

Some dieticians shoot the idea down, saying the Aztecs could get the eight necessary amino acids from their staple crops corn and beans. But to ensure their bodies absorbed the corn and beans as amino acids instead of just packing them away as energy, the Aztecs would have to've eaten large quantities of both simultaneously – and according to Diego Durán, the poor could not harvest corn and beans simultaneously. Consider also the effect of a crop failure or two, which is often a trigger for war even in the Old World (the French Revolution, for example, was preceded by crop failures brought on by the 1783 eruption of Laki in Iceland). Crop failures mean masses of starving, desperate people, and those tend not to lie down and die quietly. If they're already craving animal fats and have some military training – and the culture's open to the possibility of cannibalism – the solution is obvious.

No, this is just a beef fillet. But apparently it looks pretty similar.

The City of the Gods
The thing is, it wasn't always like this. A thousand years before Tenochtitlán, another city stood in the Valley of Mexico, a place of relative peace and prosperity. Teotihuacán ("Tyo-tee-wah-can"), the Birthplace of the Gods, was already in ruins when the Aztecs arrived, and we know almost nothing about the people who built it – who they were, what language they spoke, even what they called their city (the name is Aztec). The first proper city in the Americas, from 300 to 700 CE it expanded into an architectural masterpiece. Through the city runs the arrow-straight Avenue of the Dead, nearly two-miles long and lined with low, smaller stone pyramids. Beside this Avenue rises the flat-topped Pyramid of the Sun, 220 metres square at the base and 230 metres high, or as high as a 20 storey building – a colossal edifice of earth and sun-baked brick sheathed with stone. The smaller Pyramid of the Moon rises at the northern end of the Avenue, and at its southern end is a great square enclosure walled with massive buildings called the Citadel. Beyond the ceremonial centre lie the remains of humbler dwellings, covering almost 20 square kilometres, making it larger than Imperial Rome.

Fully occupied, it would have been home to some 50,000 people – an unprecedented number for the Americas, which points to some major improvements in agriculture. And indeed, Teotihuacán is believed to have been the culture that perfected the chinampa, the "floating garden" system of agriculture. Artificial islands built in the shallow lakes of the region, chinampas were constructed from reeds and silt from the lake bottom anchored at the corners by willow or cypress trees. They were enormously productive, as the soil was rich and refreshing it was as simple as dredging up a new layer of silt. An important difference from Old World farming, however, was the layout: in the Old World fields were readied by a plough pulled by a beast of burden and then sowed by broadcast seeding, which meant fields tended to be dedicated to a single crop. In the Americas all field prep had to be done by human muscle. There were no animals that could draw a plough, so fields were tilled by hand-held sticks or hoes, and seeds were planted individually. Most New World fields thus came to be mixed gardens of many crops planted together – squash, pumpkins, beans, chillies and of course, corn. To us it sounds more like a veggie patch, but for 1,500 years it fed major world civilisations.

Although well fed, Teotihuacán wasn't quite bloodless, worshipping, among others, the fucking awful Xipe Totec, who had the nastiest rites of all the Mesoamerican gods – a young woman's skin was removed in one piece (and none of my sources will confirm she was dead when they did this) and then worn by a priest like a wet onesie, whereupon he danced to commemorate the arrival of spring, when nature puts on a new coat of vegetation. Why he couldn't just change his robe or something, I don't know. But for its time and place, Teotihuacán seems to've been a relatively peaceful place. Warriors and weapons aren't prominent in the artwork there, and their principle god seems to have been the rain god, Tlaloc. See "major improvements in agriculture," above.

But then suddenly, it all fell apart. Around the year 700, about the same time as the Classical Mayans, Teotihuacán fell, was looted and burned. Its people were massacred or dispersed, and its influence suddenly ceased. The Chichimecs, or Sons of the Dog – nomadic tribes from the north who had probably always been there – had finally broken through. They were a warlike people, so their god was the fierce Tezcatlipoca ("Tez-cat-lee-poke-ah"), the Smoked Mirror. Another confusing name: the Mesoamericans made mirrors out of obsidian, so calling him the Smoked Mirror made him a god of obsidian. It was the same as us calling a deity the Lord of Steel (which I'm pretty sure is a Dio album): he was a war god, in other words, his nagual was the jaguar, and his chosen were the aforementioned Jaguar Warriors. He was emphatically not a god hopeychange, and his people could no longer be held off by the Teotihuacán king's army.

For the longest time we didn't know why, and debate is ongoing, but evidence seems to point to internal unrest: it seems a great civilisation really isn't conquered from without until it has destroyed itself from within. Or at least been seriously weakened. There is evidence of population decline in the 6th Century, with more young skeletons showing signs of malnutrition. It seems the people of Teotihuacán were no longer being fed. The chinampas had failed them.

Why? Because of droughts that followed the Extreme Weather Events of 535-536, an 18-month period of cloudy skies, crop failures and famines that was described in both Roman and Chinese historical accounts. And for that, current thinking blames the eruption of the Lake Ilopango volcano in El Salvador. This Plinian-type eruption is now known to have occurred at about this time and was much bigger than previously believed, killing about 100,000 people outright and displacing about 400,000 more. Its signature can be found all over the region in the form of a thick, white layer of tephra, locally called the tierra blanca joven, or Young White Earth. Researchers have discovered TBJ deposits as far afield as Nicaragua, Honduras and in offshore deposits, indicating the eruption produced five times the volume of ash and debris than originally estimated, now calculated at 84 cubic kilometers (for comparison, Mount St Helens was a puny 0.25 cubic kilometres). It was the second-largest volcanic eruption of the last 200,000 years, beaten only by the 1815 eruption of Tambora, which blasted 160 cubic kilometres into the air and caused the 1816 Year Without a Summer. (Still dwarfed by the Toba eruption of 75,000 years ago, which put 2,800 cubic kilometres of rock into the air and reduced the human population to just 10,000, maybe as few as 40 breeding pairs. It was the closest human beings ever got to extinction – so far, at least).

Now imagine what that did to farming in the region. Actually, you don't need to imagine, this article about the Mayan Cultural Collapse spells it out in great detail. Again, Apocalypto: remember the scenes leading into the city, full of starving, diseased people and fields of swaying dead crops? Mel got that right, but it actually happened some 700 years earlier than his movie. What he didn't get right was the idea of hunter-gatherers living in virgin jungle. In truth, by the peak of the Classical Mayan civilisation they were packing in up to 240 people per square kilometre in rural areas, and over a thousand in the cities.

Today the Petén, geographically the largest province in Guatemala, has a population of 400,000, living in isolated towns scattered through a forested wilderness. In the eighth century, by some estimates, ten million people lived in the Maya lowlands. In fact, settlements around centers like Tikal reached population densities of up to 2,600 people per square mile. That’s more than half the population density of modern-day New York City. The landscape was an almost unbroken fabric of intensely cultivated farms, gardens, and villages, linked by a web of trails and Sacbe'ob, paved causeways connecting monumental city-states.

It would have been a similar situation further north, but with chinampas rather than the Mayan slash-and-burn farms. And when that many people suddenly can't eat, as I said, they don't usually lie down and die quietly – they pick up a weapon and go after neighbouring tribes, killing or driving them off and taking their food. In an area like Mexico, short on wild game, sooner or later someone is going to give cannibalism a shot (after all, people were the only things around there were more of than needed...) and it only takes one tribe to make it popular, because suddenly their warriors will be well fed and have a major competitive advantage. From there every other tribe will ultimately have to adopt cannibalism or be annihilated.

Thus, Aztecs.

The Last Twitches of Conscience
This is why I consider vegans in the same category as people who place their CDs label side down: conscientious, but misguided. Human beings need animal protein, and we'll go to some insane lengths to get it. That said, I actually agree with vegans that we need to stop harvesting animals for meat, but rather because it's inefficient than because it's unethical. Every one of us needs animal protein, but thanks to the ten-to-one rule I mentioned earlier, we can't possibly grow enough animals to provide it for 7 billion plus. So I'm putting a lot of hope in the synthetic beef idea, or the Beyond Meat guys who are finding ways to make it directly from plants – meat without animals, a beautiful dream.

Because make no mistake, we're heading for exactly the same scenario that created the Aztecs – overpopulation, climate change, no shortage of calories, but completely starved of animal proteins. It's science or soylent green.

So discussions of the morality of the Aztec culture are irrelevant in my view – they did what they had to do to survive, just like everyone else on this planet. They just found a religion to justify it. But they were still human beings, capable of love and compassion and thought and reason, so that doesn't mean they were happy about it. Which brings us to the figure of Quetzalcóatl.

Quetzalcóatl ("Kwet-zal-co-aht-el," or Kukulkan to the Mayans), was the Feathered Serpent, the most famous of the Mesoamerican gods. In his very early days Quetzalcóatl the god was difficult to separate from Quetzalcóatl the man, a Toltec king first called Topiltzin, who changed his name when his reign over the city of Tollan really got into gear. I wonder if maybe we shouldn't separate them at all; ancestors often become gods in the passing of time, and Topiltzin was a very fondly-remembered king, a culture hero, lawgiver and bringer of peace and prosperity to his people. From there to god of wind, spirit and learning, bringer of knowledge and civilisation, isn't such a huge step.

And like King Arthur, Barbarossa and Ghenghis Khan, his people couldn't let him go, believing that one day he would return. According to the tradition, Quetzalcóatl promised to come back in the year of One Reed, some 500 years in the future, and he would be coming from the east, from over the sea. When Moctezuma II, the final Aztec tlatoani, met Hernán Cortés, the ultimate conquistador, popular history says he thought he was meeting a living god whose return had long been foretold. It might be more Spanish propaganda, but his actions were certainly not those of a ruler meeting a military threat. For what it's worth, Moctezuma seems to have been a very different tlatoani from his predecessors, not nearly as into sacrifice with his own hands, and devoted to the peaceful and nerdy Quetzalcóatl. This means a great deal, because centuries earlier Quetzalcóatl – or Topiltzin, who's basically the same thing – tried to forbid human sacrifice once and for all. Quetzalcóatl promised to return to end the killing and usher in a new age of peace and prosperity. The 300 years from the fall of Teotihuacán to the rise of the Toltecs were a long war between the followers of Quetzalcóatl and the followers of Tezcatlipoca, and for the reasons outlined above, the followers of Tezcatlipoca won.

But right from the beginning, their conscience told them their cannibal empire would have to end one day. The clock was always ticking.

Post-scriptum
If you're as tickled by history as I am, two final things: apparently, the outline of Tenochtitlán's island is still preserved in the modern streets of Mexico City, if you know what to look for. In fact, the outline of the city itself conforms pretty closely to the shores of Lake Texcoco, which was drained and reclaimed some time in the 1700s. Amazing to think that the Autodromo Hermanos Rodriguez, a temple to my other great passion, now sits more or less where Lake Xochimilco used to be!

And although a bit of a zombie language, Náhuatl still gave English such useful words as tomato (from xitomatl), chilli (chīlli), coyote (cóyotl) and of course chocolate (from xocolatl, or Bitter Water – Aztec drinking chocolate tasted like black coffee mixed with red wine (better than it sounds!), and it wasn't until Europeans added milk and sugar in the 19th Century that what we call chocolate was invented. You can find a recipe for the real stuff here; just remember to start with raw cacao, not cocoa).

And you only have to go as far as YouTube to hear the music of Náhuatl spoken again.