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  • James Houser

August 13, 1521 - Spanish Conquest of the Aztecs and Battle of Tenochtitlan

Updated: Jun 12, 2021

August 13, 1521. After three months of fighting, the Spanish conquistadors of Hernan Cortes finally extinguish the last resistance in the Aztec city of Tenochtitlan. Even if Cortes could not have won his triumph without the help of 50,000+ native allies, the victory begins a new, bitter reality for the peoples of the Americas. The realities of disease, conquest and slavery herald their ultimate doom.

One of the great myths of the European conquest of the Americas is the notion of a few brave soldiers and commanders triumphing over the faceless hordes of the native resistance. In many cases, this is misleading above all in one major fact: the Spanish conquistadors could not have carried out what they did without either cooperation or outright alliance with local groups and tribes. Of course, the Spanish would completely screw these people over in the future, but that doesn’t change the reality. All I’m saying is that, as terrible as the Spanish did end up being (and they WERE), they would have had a much harder time conquering the New World if the Aztecs hadn’t been such complete assholes.

The Aztec rise to power had been relatively recent, and they were still a rising power by the time Cortes arrived on the shores of modern-day Mexico. In the 1200s, Central America was dominated by the Toltec peoples, who experienced an unexplained collapse around that time. The ensuing power vacuum pulled in migratory tribes from the north, among them a group known as the Aztecs. They drifted into the valley of central Mexico and became subject to whichever local tribe was able to achieve hegemony. The Aztecs settled on the shores of Lake Texcoco and built up large islands within the lake itself – the interconnected set of islands that would later become the great city of Tenochtitlan. By the early 1400s, they had joined with the other two tribes of Texcoco and Tlacopan to form the Triple Alliance, the military combination that would come to dominate Mexico.

The Triple Alliance was a conglomeration of city-states that came to dominate other city-states. Compare the technology levels and political organization with, say, ancient India or the early Italian peninsula, with Tenochtitlan playing the part of Rome. A dominant city-state expands its borders, not only through military conquest, but through alliance and confederation. The Triple Alliance worked well together for 90 years, but soon the Aztecs came to be the dominant power. Soon the Aztec/Triple Alliance Empire spread from the Atlantic to the Pacific, and as far south as the modern border of Mexico. Two tribes – the Tlaxaltecs and the Tarascans – remained to resist, and although the Aztecs constantly warred against these lesser powers, they could not overcome them.

The Aztecs led the expansive tendencies of the Triple Alliance in part because of their religion, which taught that history moved in cycles, the end of which came with the death of the sun. To keep the sun healthy and shining, he required sacrifice, and well…those guys don’t look particularly useful, so they can be the sacrifices. The pyramids that dominated Tenochtitlan itself were large altars that saw the daily sacrifice of prisoners of war captured in the constant fighting that marked the Aztec hegemony. On religious festival days, the priests might execute several thousand. As you can imagine, this practice did NOT generate loyalty among conquered peoples.

Just as a note – this is about the same time the Inquisitions, and the genocides of Jewish and Muslim populations of Spain, are taking off in Europe. And that’s before we get to what actually happened to the natives of Mexico after the Spanish took over. So, before we judge too harshly, let’s remember that the people about to knock the Aztecs off their block weren’t exactly pillars of virtue, eh?

Either way, the Aztec Empire was a healthy and growing institution. Tenochtitlan had a population of 200,000, which makes it about the size of Paris or Constantinople in the same time frame, and the whole Aztec population rang about 6 million. When Montezuma II came to power in 1502, the Aztec Empire was the dominant force in the region, and had a highly developed bureaucracy and tax structure, along with a vibrant economy and surprisingly good health. Its largest market hosted as many as 60,000 people on market days.

And then Cortes happened.

Hernan Cortes was one of the great captains of history and a terrible human being. It is odd how those tend to go hand in hand – or maybe not so odd after all, since the same qualities that make a good general also tend to make someone cruel and sociopathic. Cortes had come to the newly discovered Caribbean Islands as a young man and helped in the conquest of Cuba, where he came into the favor of the governor, Diego Velasquez.

Velasquez soon soured on Cortes when he recognized his young protégé’s ambition, ruthlessness and backstabbing character. In 1519, after nearly two decades of experience in the New World and on multiple expeditions, Cortes – against Velasquez’ explicit orders - sailed for Mexico with 11 ships, 500 men, 13 horses, and a few cannons.

Cortes was out on a limb when he landed on the coast of the Aztec Empire. He could not rely on any support from Cuba since he had launched his adventure by basically starting a mutiny and was now technically a criminal. To make sure his men got the message, Cortes burned his ships as his small cadre of soldiers watched silently. There was no going back: they would conquer or die. Hernan Cortes as (I repeat, a monster of a human being) but a great leader emerged from this incident. Equate him with Genghis Khan, Caesar, or Hitler if you like, but he knew how to motivate people.

Cortes made a few key allies quickly. He recruited a priest who had been a captive of the Mayans and was able to translate with the locals. After a few battles against the Tabasco people, Cortes accepted their surrender and received a few captives – including the Nahua woman Marina, who would become his mistress and the father of his son Martin. Marina – better known as La Malinche – spoke Nahuatl, the language of the Aztecs. Finally, the conquistador met with several representatives of Montezuma II, and Cortes requested a meeting. The Aztec diplomats, seeing that there was no way this would go well, refused, but Cortes was determined to make the trip anyway.

About this time, supposedly, the local peoples mistook the Spanish for gods – specifically the white god Quetzalcoatl, who had promised to return to the world. While some people undoubtedly did make this assumption, it is a drastic exaggeration to claim that all of Mexico saw Cortes and his small cadre as gods. Most Aztecs and other groups saw Cortes and his men as MEN – even if they were well-armored and outfitted with scary weapons and weird animals. The main source claiming that the Spanish were mistaken for Gods was…Cortes himself, who would certainly have no problem exaggerating his own feats and downplaying the intelligence of these “savages.” In fact, the Aztecs and their subject peoples both saw the Spanish invaders as tools to be used for their own ends. Each group thought they were using the other.

Cortes began his march into the interior in August 1519, gaining allies by reputation or force. After a few initial skirmishes, he made good friends with the Tlaxcalans who – after a few battles – started wondering if these weird white people would be useful allies against the Aztecs. The Tlaxcalans warned Cortes that the route the Aztecs wanted him to travel was surely an ambush. When Cortes slipped by this planned trap, Montezuma II was forced to confront the possibility that maybe they were gods, after all. Montezuma wasn’t the sharpest knife in the drawer; most of his advisors saw right through Cortes.

When Cortes entered Tenochtitlan on November 8, 1519, he was amazed at the vast wealth and beauty of the city. After only a few weeks in the city, though, he learned that the garrison he had left back on the coast had been attacked by the Aztec governor. Cortes seized on this pretext to take Montezuma hostage and tried to rule through him. The Spanish soldiers with their steel armor, cannons, and mounted officers were a match individually for anything the Aztecs had to throw at him. Cortes’ use of Montezuma as a puppet made him cocky, though, and he went a step too far when he tried to dismantle the Aztec religion in favor of Catholicism.

In the midst of all this disquiet, Cortes received word that Diego Velasquez had sent a second expedition – not to conquer the Aztecs, but to track down and arrest Cortes for his illegal invasion. For a few weeks, Cortes negotiated with the expedition while carefully leaking word of the riches of the Aztecs, subverting many of the governor’s men to his cause. In the spring of 1520, Cortes led about 250 men against the 750 of the new army, and in a stunning victory he utterly defeated them and incorporated them into his own force.

In Cortes’ absence, though, things went south fast. By the time Cortes returned to Tenochtitlan, the city was in upheaval, and Montezuma refused to cooperate. The Aztecs appointed his brother Cuitlahuac as the new Emperor and by June 1520 were launching attacks on Cortes’ position in the palace. The limited number of Spaniards – 1100 with their new recruits – were besieged by tens of thousands of angry Aztec citizens, who swarmed them with javelins and arrows. Even if fire from cannons and firearms tore holes in the Aztec ranks, their numbers were simply too much, and even Cortes’ personal leadership could not stem the tide. When Cortes placed Montezuma on a rooftop to speak to his people, the dethroned Emperor was killed by the missiles of his former subjects.

Soon the Spaniards’ only hope was escape. Despite their Tlaxcalan allies, the Spanish were heavily outnumbered, and had to fight their way out of the city for two days, seeking cover in structures and delayed by the need to repair bridges that had been destroyed. They had to hack through one Aztec barricade after another, and only when they had built a portable bridge (a remarkable engineering feat) could the remaining conquistadores escape. On the night of June 30-July 1, the Noche Triste (night of sorrows), Cortes and his expedition escaped from Tenochtitlan at the cost of all their gold, 600 men, most of their horses and all of their cannon. There is still a famous tree where Cortes wept after the loss of most of his expedition (don’t feel too bad for him).

The Aztecs pursued Cortes’ retreating force, and on July 7 the Spaniards and Tlaxcalans made a stand at Otumba. In an all-day battle, Spanish discipline and Tlaxcalan savvy managed to defeat many thousands of Aztec assailants. This victory gave Cortes the space to rebuild his army and smuggle in more horses, cannon and gunpowder from Cuba and Jamica. A new, accidental ally aided Cortes. The epidemic of smallpox had been carried by an escaped slave from Cuba to Mexico, and it soon affected the whole peninsula. The Emperor Cuitlahuac died, to be succeeded by Cuauhtemoc, one of Montezuma’s sons-in-law. The smallpox epidemic drastically weakened the Aztecs at a critical moment when numbers were their only ally.

By Christmas 1520, Cortes was ready to march. He began by seizing every town around the shores of Lake Texcoco, completely surrounding Tenochtitlan by the water routes. His army by now consisted of 86 cavalry, 118 musketmen, and more than 700 armored infantry with swords and pikes, along with 50,000 Tlaxcalans with their cloth armor and obsidian-tipped hacking and slashing weapons. Even if the Mesoamericans did not have steel or gunpowder, Cortes could do nothing with less than 1,000 men against the might of the Aztec Empire, and the Tlaxcalans made the conquest possible.

On May 26, 1521, Cortes began the final siege of Tenochtitlan. It was a protracted, bloody affair, with many small battles and desperate struggles, feats of engineering and courage on both sides, and a ruthlessness on a massive scale. The Spaniards and their allies had to advance across the narrow causeways above the surface of the lake, with the assistance of purpose-built boats dragged for miles over rolling logs; Cortes led the makeshift navy as his men fought along the narrow paths into the great city.

The battle ensued for weeks. Cortes’ men destroyed the aqueduct that brought water into the city. On May 31, a swarm of Aztec canoes nearly overcame the Spanish fleet, but the broadsides from their cannons made Cortes the master of Lake Texcoco. The Aztecs cut gaps in the causeways, but this allowed the Spanish fleet to sail in and blast the defenders with artillery while new bridges were constructed. Soon the Spaniards were across the causeways and approaching Tenochtitlan itself.

For 10 weeks, the battle on the edge of the city raged. Each day, the Spaniards saw their prisoners taken to the top of the pyramid and executed. The lack of fresh water, the smallpox epidemic, and the political turmoil inside the city took its toll. Occasional Aztec ambushes kept the Spanish on their toes, and they moved cautiously into the city center. The rainy season worked against the Spaniards, and the Aztecs saw this as a golden opportunity to call for help – but they had sacrificed too many people on their pyramid, and no one was coming to help the bloody rulers of Tenochtitlan.

Finally, on August 13, 1521, Cortes launched his final assault, and the last 15,000 defenders of the Aztec Empire died on the slopes of their pyramids. The streets of Tenochtitlan ran red with blood as Cortes stood triumphant after a struggle of two and a half years. The Spanish had conquered the heart of Mexico.

Of course, that wasn’t the end, and it took decades more for the conquistadors to subdue the rest of the country – but in so doing, they completely dismantled Mesoamerican society. Disease did the vast majority of the work, in some places killing almost 90 percent of the original population of Mexico. This was not intentional on the part of the Spanish, of course, but the slavery and cultural genocide certainly were, and these played their part in the collapse of Aztec culture. Within a generation, the Nahuatl language and religious practice ceased to exist, replaced with Spanish and Catholicism. The Aztec gold artwork was melted down into the bullion that would fuel the Spanish Empire for the next century and a half, making Spain the great power of Europe.

Tenochtitlan would become the administrative center of New Spain and receive a new name – Mexico City. The Spanish allies would not be spared; soon they, too, would become slaves, victims of smallpox, or cogs in the machinery of European empire. None of this was inevitable, and like I said, if the Spanish hadn’t found willing allies, things might be a whole lot different. The Aztecs were in many ways more advanced than the Europeans in organization, artistry, societal functions and commerce, and there are multiple examples of countries like Ethiopia or Japan that got ahold of European technology and managed to preserve their independence. Had things happened differently, there might not be a Spanish-speaking Mexico today.

Of course, there is. A Spanish-speaking Latin America, for that matter, and Cortes kicked open the door to that conquest. His ruthlessness, ambition, and ultimate triumph would exemplify the tragic, world-changing Spanish conquest of the Americas.

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