The Rise and Fall of the Aztec Empire

Before the Aztecs established a society that many view to be equal parts magnificent and fascinating, they were migrants. Hailing from the arid regions of Northern Mexico or the Southwestern United States, they were hunter-gatherers who were in search of a new home.

According to Aztec myth, they migrated from Aztlan in search of a new home, under the divine direction of their patron god, Huitzilopochtli. As the legend goes, Huitzilopochtli directed them by placing a sign — to settle where they could see a giant eagle consuming a snake while perched on a cactus. They reportedly found this on a small island in one of the five interconnected lakes, and founded Tenochtitlan, their new capital. This is where the Aztec Empire's watery foundations began to be built upon in 1325 C.E.

The area where the Aztec civilisation was built upon was within the Valley of Mexico, and the society enjoyed a mild climate. The area was situated between high mountain ranges, and had plentiful lakes that allowed them to enjoy a diet of fish. Overall, the growth of the Aztec empire coincided with a wet climate, which allowed them to maximise agricultural output. The rich soil, mild climate and abundance of water sources enabled them to sustain a high population and to harvest at least three times annually.

The Aztecs were agriculturalists, and the crops they grew included maize, beans, potatoes, avocados and tomatoes among others. Not only were they farmers, they also hunted game such as rabbit, wild turkey, coyotes and snakes.

Perhaps one of the most interesting facets is their sophisticated agricultural and cultivation system — one that leveraged their environmental surroundings, and aided their transition from their humble beginnings into their reputation as warriors living in a city-state empire.

Chinampas: The Floating Farms

So how did the Aztecs build an agricultural system that enabled them to expand and strengthen their empire? The answer lies in their chinampas, or artificial islands used to grow crops.

To build the chinampas, the Aztecs formed rectangles that varied in size. The typical chinampa spanned around 90 metres in length and were around 4 to 9 metres in width. These measurements were then marked using stakes, and the outline filled with mud and organic materials until the mixture exceeded the lake's water level. To navigate around each chinampas, canoes were used. These channels provided crop irrigation and an easy way to transport products to market.

The benefits of this system were twofold — for one, this allowed them to both produce crops and irrigate efficiently, as they were built upon water. Secondly, transportation was simplified due to the ease of travelling around chinampas with canoes.

Up to 20,000 hectares may have been under irrigation in the Valley of Mexico alone.

The Aztecs were environmentally-savvy. After all, this was how they transitioned from being hunter-gatherers to inhabitants of a fearsome empire.

Yet, as we can see through the example of chinampas, the Aztec established an efficient and economic waste management system. Besides being agents of high agricultural output, the chinampas also allowed for the easy recycling of nutrients. The waste that was used on the chinampas, such as food leftovers and human excrement, fertilised the crops. This helped protect the natural environment while capitalising on the mild climate and irrigation systems.

Further, urine was even used as fabric dye. During Montezuma II's rule between 1502 and 1520 — one that would be upended by the arrival of the Spanish — littering and dumping waste warranted punishment. In fact, a person could be sentenced to death for cutting down a tree.

Nowadays, many of the wastes we put out into the environment remains as pollution, negatively affecting our environment. For the Aztecs, the risk of water, air and land pollution were mitigated by recycling organic waste from farms and human excrement. In this way, they were able to protect their environment and maintain its equilibrium while producing high agricultural output.

As the Aztec Empire grew from strength to strength, they were about to meet a formidable and foreign enemy. By February 1519, Hernan Cortés' ships reached Yucatan on the Mexican coast. Cortés, of course, was a Spanish explorer who would later play a decisive role in the fall of the empire. The Spanish, having discovered Mexico in 1518, had goals to settle the area and to convert its native people to Christianity.

As Cortés' expedition continued, he landed at Tabasco in March 1519. Fortunately for him, the local Indians resented the Aztecs, allowing him to gain intelligence from them. Cortés was an efficient leader, but he was not the supreme — Montezuma II, the Aztec emperor, was. While Cortés took over Veracruz on July 13, 1519, he used the opportunity to arrange a meeting with Montezuma II, but was refused. Despite this, he disciplined his army and formed alliances with neighbouring tribes.

During his journey to Tenochtitlan, Cortés found allies with the Totonacs and the Nahua people of Tlaxcala. The Otomi people and the Tlaxcalans were initially against the Spanish. Yet, after discovering that they were also against Montezuma II, they forged alliances with them.

In a show of force on October of 1519, Cortés and his army marched to Cholula, the second-largest city in Mexico at the time, pillaging and killing thousands of individuals who were part of the nobility, and even burned the city. He was accompanied by around 1,000 Tlaxcalteca warriors. The city suffered terribly and uprooted its leadership as well as destroying its environment.

On November 8, 1519, took Montezuma II hostage, and on July 1, 1520, he was killed.

The death of Montezuma II, however, did not signal the complete destruction of the Aztec Empire. The Spanish assault on the empire did not come without consequences. When Cortés and his army left the emperor's palace on June 30, 1520, they were attacked in what was to be known as 'La Noche Triste'. The Spanish were denied an escape route by the Mexica people, who damaged the causeways and bridges to prevent them from an easy escape. Indeed, they suffered many casualties as they made their way to Tacuba — Cortés would lose 600 out of around 1,200 Spanish soldiers, alongside thousands of Tlaxcalan allies, and seventy of his hundred horses. 

However, this was not to be the last conflict. The Battle of Otumba was fought between the Aztec and allied forces, against the Spanish and Tlaxcalan allies. The battle, which occurred on July 7, 1520 in Temalcatitlan, a plain near Otumba, yielded a victory for the Spanish forces. Following this battle, they reached Tlaxcala and were assisted with reinforcements from Cuba.

As we know, agriculture played a key role in providing Aztec troops with the required supplies to maximise their chance of success against the Spanish and their allies, thereby playing a great role in military outcomes. However, the Aztecs were highly reliant on food supplies from their capital, Tenochtitlan. Indeed, one of the main advantages that Cortés would leverage is that the Spanish forces and its allies were able to rely on food sources other than those that were supplied from the Aztec capital.

Cortés established an attrition policy regarding supplies from Tenochtitlan by blocking supplies and ultimately reducing the fighting power of the Aztec forces and their allies.

It was only a year later that Cortés was finally able to conquer Tenochtitlan. During this time, he forged new alliances, and took advantage of the weakening Aztec population thanks to sabotaging agricultural exports.

Yet, this was not the only factor that came into play — diseases played a key role too.

Smallpox — it was the Spanish conquistadors' microscopic weapon.

The first case of smallpox appeared in Central Mexico during the 1520s. In fact, its appearance among the Aztec population is often attributed to Francisco Eguia, a black slave known to have been infected in early 1520. The disease was foreign to the area, and was introduced only during European contact in the Americas. In late September or early October of 1520, the smallpox outbreak became a devastating presence in the Aztec capital of Tenochtitlan. In fact, this outbreak was expedited as an event that occurred just two to three months following 'La Noche Triste' on June 30, 1520.

As a result, Tenochtitlan's population was reduced by around 40% in one year as a result of this outbreak. This population collapse due to Spanish forces and its environmental repercussions caused sediment to bury irrigation canals, erasing signs of intricate hydraulic features that demarcated the various regions of the Aztec world.

The Aztec empire was a living example of a society that prioritised waste-minisming practices through their daily lives and agricultural methods, which in turn protected the environment in which they were living in. Yet, the arrival of the Spanish and their allied forces caused mass disruption to their ways of living.

Following the fall of Tenochtitlan and subsequently, the entirety of the Aztec Empire, the new Spanish overlords broke apart the Aztec waste management system and established the beginnings of a city we know today — Mexico City. Previously, the Aztecs were able to control floodwaters through a complex system that involved the use of canals and levees — techniques the Spanish did not retain. As a result, the lakes upon which the Aztec Empire had ruled on were drained. Today, only a basin remains and the city that was so famously built upon this lake was no more.

This change of empires, so to speak, resulted in the greatest environmental shift this Mesoamerican region had experienced in the last millennium. Once full of water, the natural environment had been effectively destroyed. Today, Mexico City experiences water shortage in that region — a starkly different image to the Mesoamerican Venice that was once the heartland of the Aztec Empire.