Episode 2: The Aztecs: From empire to A.I.

Five-hundred years after the fall of Tenochtitlan, Aztec culture endures, thanks to its descendants, protectors, and centuries-old documents that are moving the Aztec language and lore into the age of AI.

Tenochtitlan, the ancient Aztec capital, is now known as Mexico City.
Photograph by Keystone View Company

Spain’s victory over the Aztec launches colonization of Mexico, but Aztec culture will survive for centuries through preservation and practice. Aztec codices—16th-century Rosetta Stones that preserved Aztec language and deeds—laid a foundation that scholars are building on today as Aztec culture is woven into AI.


AMY BRIGGS (HOST): So we’re in a village in rural Mexico, about a day’s drive from Mexico City. You can hear music emanating from a little house that has this thatched roof. But inside, that’s where the action is. There’s a ceremony going on.

ALAN SANDSTROM (ETHNOGRAPHER): The rituals often take place in little shrines, which are small houses.

BRIGGS: That’s Alan Sandstrom, an ethnographer at Purdue University Fort Wayne, who spent decades researching the village and the people who live here. He approaches the house, and he joins the 40 or so villagers inside.

SANDSTROM: There’d be musicians over in this corner playing guitar and violin music. The place would be filled with copal incense smoke, like a fog of this very beautiful smelling—it's like a pine, like a Christmas tree or something smell, you know? And they'd be dancing to the music, and maybe could be a dozen women in beautiful costumes, dancing.

BRIGGS: Some people decorate an altar with marigolds.   

SANDSTROM: The whole thing would be this beautiful yellow-orange. They'd make beautiful pinwheels out of coyol palm and flowers and put them on the altar. Those stand for the stars in the sky.

BRIGGS: Meanwhile, others are making thousands of ritual paper figures—cutouts meant to embody the gods—and then carefully place them on the altar. And then there’s this man, and he starts chanting. So the ritual lasts for a full week, going on day and night with no rest. These villagers? They’re descendants of the Aztec.

So the language you’re hearing? It’s not Spanish. The villagers still speak Nahuatl, which is the same language the Aztec spoke. The ritual—the paper figures, the marigolds, the dancing—it dates back centuries, before any Europeans set foot in the Americas.

SANDSTROM: I think it's 90 percent Native American and with a 10 percent add-on of Catholicism.

BRIGGS: So 500 years ago this summer, the Aztec Empire came to an end when their local rivals teamed up with some new arrivals to the Americas, the Spaniards. Their capital city, Tenochtitlan, fell, and Spanish forces took over. But then what happens?

I’m Amy Briggs, executive editor of National Geographic History magazine. And this is Overheard: a show where we eavesdrop on the wild conversations we have here at Nat Geo. And follow them to the edges of our big, weird, beautiful world.

This week, in honor of this anniversary, we’re going to Mexico. We’re going to explore the legacy of the Aztec: We’ll investigate the rare records that miraculously survived the Spanish Inquisition, learn what happens when you feed Aztec legends into a computer, and meet modern Aztec descendants.

JIM TAGGART (HISTORIAN): He said, “Are you working with the devil?” And I said, “Yes, I am.” But I didn’t know what he had said.

BRIGGS: More after the break.

History magazine just featured a cover story on the Aztec age, looking back at the people who dominated central and southern Mexico in the 1300s. We know them today as the Aztec, but that wasn’t what they called themselves.

They were known as the Mexica, which is where Mexico gets its name. They, like other peoples in the region, spoke a language called Nahuatl.

The Mexica’s ancestral home was a place called Aztlán. Archaeologists don’t know its exact location, but most believe it’s in northern Mexico. And the word “Aztec” comes from this name.

And we should let you know now: the terms Aztec, Nahua, Mexica—they’re all different, but they overlap a lot, so it’s hard to keep them separate. You’re going to notice people using them interchangeably in this episode.

So around the early 14th century, this group of Nahua traveled south from Aztlán and founded two cities that later combined into one giant city. We know it today as Mexico City, but the Mexica called it Tenochtitlan. It was from there that their empire would grow.

ANDRÉS RESÉNDEZ (HISTORIAN): This lowly wandering group—outlying group from the north—arrived into central Mexico and founded a stable city-state.

BRIGGS: That’s Andrés Reséndez, a history professor at the University of California, Davis.

RESÉNDEZ: So basically, it was a little bit like the mafia. The Aztec warriors went out there. They intimidated other city-states into providing tributes. And we have a beautiful Matrícula de Tributos, a beautiful document showing, I don't know, hundreds of—400 city-states owing tribute, sending tribute, to Tenochtitlan, their center, their city-state.

BRIGGS: While the Aztec are building an empire, Spain is trying to do the same thing. In the early 1500s, Spain gets very excited about the Americas and begins colonizing Caribbean islands. Then they turn their attention westward, and in 1519 they send an expedition to Mexico led by Hernán Cortés.

So let's just talk briefly about what happens in 1519. Cortés shows up. What's the reaction at first? Is he welcomed? Are people afraid?

RESÉNDEZ: This was a fluid situation in which different city-states were either subservient to others or trying to overthrow the subservience. And so evidently everybody was trying to figure out how to better use these strangers in their ongoing wars.

BRIGGS: It's almost like he shows up in the middle of the story.

RESÉNDEZ: Exactly. Right. He throws himself in the middle of this active conflict going on.

BRIGGS: So Cortés forges an alliance with various Indigenous groups and decides to take over Tenochtitlan. So their combined forces descended on the city in May 1521.

RESÉNDEZ: One definite technological advantage on the part of the Spanish was their artillery. So if they could just get close enough to the city, they could use their very destructive artillery. And there was nothing the Aztecs could do with their own weapons to stop that.

BRIGGS: The Aztec surrender on August 13, 1521, and the Spanish take over.

RESÉNDEZ: And eventually they decided to build a Spanish city on top of the Aztec city, which is why today the main cathedral and the National Palace lay just a few steps from the ruins of the main temple of the Aztecs.

BRIGGS: The following years were devastating for the Aztec. Many were enslaved. Most of the population dies from disease and poor living conditions brought on by the Spanish.

Given all that devastation, you might think that information about the Aztec Empire might be hard to come by. But lucky for us, some records survived: they’re called the Aztec codices.

They were records used for all kinds of things: keeping track of royal tributes, divining the future, delineating territories, telling stories of conquest and defeat.

The Spanish army and the clergy destroyed many of them, but Spanish monks and missionaries created their own versions that recorded Aztec glyphs alongside Nahuatl words and Spanish translations—sort of like a Rosetta Stone.

Here's Ernesto Miranda, a digital humanities instructor at Universidad del Claustro de Sor Juana in Mexico City. He took a special interest in the codices.

ERNESTO MIRANDA (DIGITAL HUMANITIES INSTRUCTOR): I mean, when you think that they destroyed all these books, it just hurts.

BRIGGS: But amazingly, some codices are still around today—held in museum collections all over the world. And when I say amazingly, I mean it. One codex was in Dresden during World War II and survived the firebombing there.

MIRANDA: The room where the codex was, it was flooded and it miraculously survived because it was sort of encapsulated in between two other books.

BRIGGS: Ernesto says you can learn a lot about Aztec culture from these codices, like their rituals and beliefs and even their beverages.

MIRANDA: After a certain age, they were allowed to drink pulque. That is this fermented drink coming from the agave, from where you get mezcal and tequila also. And only the elders were allowed to use these drinks in a non-ritual context, as well as what we call in Western tradition as magic mushrooms, or psychedelic mushrooms, that were also very common for ritual practices.

BRIGGS: But these codices aren’t just artifacts, they’re living documents.

MIRANDA: Communities every year go to the National Anthropology Museum, they take out the codice from the vault, and they do a small ritual—some reps from the community—with mezcal and some other elements from the culture, and then they take it back.

BRIGGS: In fact, these old documents are even occasionally used in current legal disputes.

MIRANDA: They might go back to that codice and say, OK, I see that this territory belonged to the family of Juan Pérez. So, and it's good proof to make a legal case in Mexico.

BRIGGS: So we have these documents, which are valuable records of how the Aztec lived back then. But how are they living now?

TAGGART: They lived pretty much as they had lived, particularly in the areas outside of the very center of Mexico City.

BRIGGS: That’s Jim Taggart, a professor of history and archaeology at Franklin and Marshall College.

Up north, the U.S. and Canada tried to wipe out Native American culture. In some cases, Native American children were sent to schools far from family and forbidden from speaking their languages, which drastically decreased the number of speakers. In Mexico, the government did encourage assimilation, but many Indigenous people were still able to keep their languages.

TAGGART: Now, there were all kinds of problems, but the Nahuas in certain regions speak very good Nahuatl. Their vocabulary is large. Their grammar is in good shape. They're very articulate, and they can tell beautiful oral narratives.

BRIGGS: That’s right. There are still Nahuatl speakers in Mexico, about 1.5 million of them. They still live in their communities, speak their language, tell their stories, and practice their religion.

And in 1968, Jim went on a quest to find them and learn about their culture. He traveled to Mexico and came upon a valley five hours from Mexico City that he knew had a Nahua community.

TAGGART: The Nahuas live in houses that are hidden. You can't really see them.

BRIGGS: The valley is so covered in trees that you can’t actually see the houses.

TAGGART: They call them chalahuite trees. They have big leaves and they provide a lot of shade.

BRIGGS: And there were also tropical fruit trees, growing bananas, oranges, papaya, mangoes.

TAGGART: Every morning a person could hear the mule trains, with their horseshoes hitting  the stones. They would be walking through the community up to the commercial center of Huahuaxtla, which was the most important town for the merchants in the area.

BRIGGS: The Nahua men dressed in white cotton trousers and shirts and the women wore blouses embroidered with mythological figures when they worked in the corn fields. And they turned that corn into tortillas.

TAGGART: The idea was to get the corn ground very finely so that the tortillas tasted like cakes. They would just melt in your mouth.

BRIGGS: That sounds wonderful.

TAGGART: They were delicious, but they were very hard to make.

BRIGGS: At the village, Jim was looking to gather stories. But he had to win over people’s trust first, and that was tricky. At one point, he attended a wake for a young man, when another man approached him.

TAGGART: He said, “Are you working with the devil?” And at that time I would answer everyone, “Well, yes.” I didn’t know what else to say. I said, “Yes, I am.” But I didn't know what he had said. And people looked at me like they thought, Where did this guy come from? But then Nacho showed up.

BRIGGS: Nacho was a Nahua man who explained what happened at the wake. He would go on to be Jim’s teacher and friend.

TAGGART: And he just turned out to be a splendid fellow. He's a very honest and very decent man. And he was four years younger than me. And so we were close enough in age, so, you know, we shared a lot of interest.

BRIGGS: Jim would end up going back and forth between Nahua villages and the U.S. for the next 44 years. Over the decades, Nacho taught Jim to speak a dialect of Nahuatl.

TAGGART: And he could also explain to me things that people said that I didn't understand because they were alluding to things that I didn't know about.

BRIGGS: So over time, Jim got something really valuable: stories. Jim would come to Nacho’s house. Nacho would hand him a piece of sweet bread and a cup of coffee.

TAGGART: They used to make delicious coffee because they used sugar made out of real sugarcane.

BRIGGS: And then Nacho would tell him stories. On one occasion, he told Jim a story that finally made Jim understand why these stories were so important to the Nahua. It started when Nacho told Jim about a mysterious sound in a nearby river.

NACHO (NAHUA STORYTELLER): The water calls out. It begins to call out in May, when the rains begin.

BRIGGS: That’s Nacho talking to Jim.

NACHO: We heard it beating a drum, marking a path. We do not know how it’s doing it. And according to what they say, they killed it. The rain gods killed it. Because it does not call out now.

BRIGGS: The rain gods are what they sound like: gods that bring rain.

NACHO: I can't tell you but there is a story about it. They say there was a boy. 

BRIGGS: It’s a story about a boy who goes to the river to gather crayfish near Nacho’s village.

NACHO: And that boy had a drum like the ones the quetzal dancers use. 

BRIGGS: The quetzal dancers are a dance group in the community.

TAGGART: Actually, Nacho's middle brother plays that drum for that group.

BRIGGS: So while gathering crayfish, the boy came to a waterfall.

TAGGART: And this girl appeared out of the water, and started talking to him and basically falling in love.

BRIGGS: And the girl, she was a mythological being in Nahua culture called an achane,  which means “water dweller.” And they can take the form of a lizard or a serpent.

TAGGART: The achane are the ones who kind of bring the terrestrial waters, make it bubble out of the ground.

BRIGGS: So the achane have a lot of downtime.

TAGGART: They just sit in the water with their mouths open and eat everything that falls into the water. Ordinarily the achane in the earlier stories is a dangerous being and often associated with the devil.

BRIGGS: But the achane in this story was friendly. She didn’t want to leave the boy.

NACHO: So she embraced him and took him into the water. 

TAGGART: And he doesn't drown. He doesn't die.

BRIGGS: He keeps playing his drum.

NACHO: For this reason, they say that it is because of that boy, when they make a fiesta—I do not know for sure myself—but according to what they say the boy marks a path with his drum.

TAGGART: The boy plays the drum with the girl, and marks the path to fiestas that occur in different times of the year.

NACHO: But now we no longer hear it. One no longer hears the water call out. 

BRIGGS: Jim doesn’t know why the Nahua don’t hear the drumming anymore.

TAGGART: One of the theories is the rain gods killed it. And the other possibility is that he was explaining really his sense of loss, having no longer cultivated a common corn and bean plot with his brothers, and because his life has changed and has changed in the community as well. So they've lost contact with the achane.

BRIGGS: This story and others made Jim realize something.

TAGGART: It took me a long time to see it. They are the way people talk about discourse, about political discourse, political events in their community.

BRIGGS: The stories aren’t just old folktales. They’re about the present. The Nahua associate the achane with the Mestizos—Mexican people whose ancestry is both Indigenous and European. They’re the largest ethnic group in Mexico. In some stories Jim collected, the achane were the animal companion spirits of local political figures who did the Mestizos' bidding.

And Jim found that the roles of the gods would change over time, based on what’s going on. For instance, before the fall of the Aztec, rain gods were kind of above human affairs.

TAGGART: So this idea of rain gods coming to the aid of people because they empathize with their circumstances, which is definitely something that developed after the conquest—this idea that gods can be empathetic.

BRIGGS: That’s in part because the rain gods became kind of a stand-in for the Nahua, mirroring the way the achane represented the Mestizos.

The rain gods and achane would frequently get into fights. The tension between the rain gods and the achane mirrors the tension between the Nahua and the Mestizos.

TAGGART: Because there's a lot of antagonism between the achane and the rain gods, explained often as envy.

BRIGGS: This concept of envy in Nahua culture is something that really struck Jim.

TAGGART: They don't even admit that they feel envious, and yet they blame everything for envy. It's considered to be a major character flaw.

BRIGGS: Envy and love are opposites. Love is about working with others.

TAGGART: If you cooperate in the family, you're going to love your family members. The opposite of this is envy, which is out for yourself. You want something so badly, you'll take it from another person. It's described as like hunger.

BRIGGS: So after the Aztec fell from power, the Nahua people and their culture survived—even after a disastrous population decline—and they continue to survive today.

SANDSTROM: There's an international interest in the Nahuatl language. And it's being taught all over the United States right now. We have colleagues teaching it at the University of Utah. One of the world's centers for the study of this language is now Warsaw, Poland.

BRIGGS: And after all, there aren’t a whole lot of Indigenous American languages that have 1.5 million speakers—if you’re going to learn one, this is a pretty useful one to know. And now, Nahuatl is making its way into the tech age.

AI (ARTIFICIAL INTELLIGENCE): Some years ago, the princess was born under the protection of the great god Huitzilopochtli.

BRIGGS: That’s the beginning of a story written by artificial intelligence. And here’s the man who made the program that wrote it.

RAFAEL PÉREZ Y PÉREZ (SCIENTIST): Yes, my name is Rafael Pérez y Pérez. I'm a scientist in computer science and artificial intelligence. My specialty is computer models of writing. I work for the Autonomous Metropolitan University in Mexico City.

BRIGGS: Rafael invented MEXICA, a computer program that writes short stories and is named after the native Mexica people. The program is designed to make stories the way the human brain makes stories. He feeds the computer things like names and places. They could have been any names or places, but Rafael wanted to use words that related to the Aztec past of his home.

PÉREZ Y PÉREZ: I have characters like the Tlatoani that was equivalent to the kings. I have the jaguar knights and the eagle knights that were warriors—like generals nowadays, let's say. And I have some common characters like farmers and fishermen. So yes, my idea is to use these kind of characters so people can know that they were part of the Mexica culture. And also locations, no? My locations are Tenochtitlan city. That, as I mentioned before, is what nowadays is Mexico City.

BRIGGS: So why was it important to you to include Aztec pieces in these stories?

PÉREZ Y PÉREZ: Because since I was very, very young, I have been taught by my family how important it is to appreciate your own culture. And this was the perfect opportunity for me to mix my computer skills with this passion I feel for my culture, for the past in this country. I admired very much all the things they did. I think we can learn a lot from them.

BRIGGS: So do you have a favorite story from the project, and can you tell us what it is?

PÉREZ Y PÉREZ Oh, yes. Let me tell you just about one that I really like because it really surprised me. It’s about this story, this princess. I will make a quick summary. This princess was kidnaped by the enemy. The jaguar knight arrived and saved her. They fell in love. But then the princess realized that the jaguar knight killed her father, and then the princess killed the jaguar knight. And then she killed herself. Mexica is a little bit sanguinary, or bloody.

BRIGGS: Rafael, that's a very heavy story.

PÉREZ Y PÉREZ: But, you know, the reason I really like this story is because it really surprised me.

BRIGGS: Princesses get into a lot of trouble in the stories MEXICA creates.

AI: Unexpectedly, the lady saw that the princess had the sacred knife that was stolen from the temple. So there was no doubt: she was the murderer of the old priest. The princess produced in the lady conflicting feelings.

BRIGGS: The computer only writes simple stories now, but that could change.

PÉREZ Y PÉREZ: And one of my plans is to make the system to write longer pieces that hopefully someday will become novels.

BRIGGS: Oh wow. There's a bunch of creative writers out there who are going to be very anxious about that.

BRIGGS: Rafael thinks that including Nahua culture isn’t just a nod to the past. It could change the future. He could, for instance, create two different programs and feed them two different sets of information and worldviews.

PÉREZ Y PÉREZ: We have a system that can, for example, produce stories from the point of view of the Mexica and a system that produces stories from the point of view of the Spanish, and then mix them.

BRIGGS: That's fascinating, to think about it.

PÉREZ Y PÉREZ: Maybe I can describe how I feel about the Spanish conquest in Mexico and all that kind of stuff, no? I'd write stories and give it to one of the MEXICAS. And I can ask some Spanish to write how they feel about the defeat of the Mexicas.

BRIGGS: And then he’d ask the two programs to produce a story together.

PÉREZ Y PÉREZ: So they will be really different points of view, and they will have to work together.

BRIGGS: Stories, after all, give us the power to see and understand the world differently. How we talk about events and groups of people affect how we relate to them. Here’s Pamela Effrein Sandstrom, an ethnographer and Alan’s wife.

PAMELA EFFREIN SANDSTROM (ETHNOGRAPHER): Today, the people crossing— the migrants from the south, from not just Mexico but El Salvador and Guatemala and all the points south, Honduras—these people that are coming by and large they do speak Spanish, but a lot of them are speaking that as a second language. These are Indigenous people, coming from Indigenous communities. Their displacement, and the situation we're in right today, might be better understood if people looked upon them as as the—

ALAN SANDSTROM: As American Indians coming across—they're related to the Ute, the Paiute, the Comanche, and the Shoshone. Their language is very related to that. These are American Indians coming across the border, to work in the fields, you know. And I wonder if people knew that if it would make a difference.

BRIGGS: For this, Rafael has an unorthodox solution.

PÉREZ Y PÉREZ: Let's have Mexicans on one side of the border writing stories, and have people in the states in the other side of the border. And let's—that stories will write, they will show their fears that. And let's put the MEXICAS to try to build a story together. What will happen there? That could be a way for people to see other perspectives, no?


Overheard at National Geographic is produced by Ilana Strauss, Brian Gutierrez, Jacob Pinter, and Laura Sim.

Our senior producer is Carla Wills

Our senior editor is Eli Chen.

Our executive producer of audio is Davar Ardalan.

Our fact-checkers are Robin Palmer and Julie Beer.

Our copy editor is Amy Kolczak.

This episode was sound-designed and engineered by Hansdale Hsu.

Special thanks to Jeff Kaufman, who filmed the Nahua ceremony.

This podcast is a production of National Geographic Partners.

Whitney Johnson is the director of visuals and immersive experiences.

Susan Goldberg is National Geographic’s editorial director.

And I’m your host, Amy Briggs. Thanks for listening.


Want more?

If you want to know more about what the Aztecs were like before 1521, check out our History magazine piece, and learn how this anniversary is playing out in Mexico especially during COVID.

Also explore: 

We only spent a few minutes with Nahua communities. To spend more time with them, take a look at Alan’s book Corn Is Our Blood: Culture and Ethnic Identity in a Contemporary Aztec Indian Village. He and Pamela also have a new book coming out in 2022 called Pilgrimage to Broken Mountain. It’s a look at Nahua sacred journeys in Mexico.

Plus, if the rain gods intrigued you, take a look at Jim’s book, The Rain Gods’ Rebellion.

To learn more about Rafael’s MEXICA AI program, check out www.rafaelperezyperez.com 

If you like what you hear and want to support more content like this, please consider a National Geographic subscription. Go to natgeo.com/explore to subscribe today.