In 1519, Spanish conquistador Hernán Cortés landed on the Mexican coast with just 600 men—and a mission to seize the fabled riches of the Aztec Empire. What followed was one of the most astonishing—and devastating—conquests in human history.
The audacity of the venture seems almost incomprehensible today. Cortés planned to conquer an empire of millions with a force smaller than a single city block’s population.
Yet within two years, the mighty Aztec Empire—which had dominated Mesoamerica for over a century—would lie in ruins, its capital city destroyed, and its civilization forever changed.
The Conquistador’s Gamble
Hernán Cortés was not supposed to be a conqueror. Born into minor Spanish nobility, he had arrived in the New World as a young colonist seeking fortune in Hispaniola and Cuba. But when Diego Velázquez, the governor of Cuba, organized an expedition to explore the Mexican coast, Cortés saw his chance for glory.
The expedition was meant to be exploratory, not conquering. But Cortés had grander ambitions. He defied Velázquez’s orders, seized control of the expedition, and set sail for Mexico with 11 ships, 16 horses, several cannons, and approximately 600 men.
Many were soldiers of fortune, others were craftsmen and sailors—few had any idea they were about to attempt one of history’s most impossible military campaigns.
When Cortés landed near present-day Veracruz in February 1519, he made a decision that revealed both his desperation and his genius: he ordered his ships destroyed. There would be no retreat. His men could conquer or die—there was no middle ground.
By the Numbers: The Impossible Odds
- Spanish Forces: 600 men, 16 horses, 32 crossbows, 13 muskets
- Aztec Empire: 15-25 million people across 80,000 square miles
- Tenochtitlán Population: 200,000-300,000 (larger than any European city)
- Aztec Warriors: Estimated 300,000+ trained fighter
The Empire of the Eagle and Serpent
The Aztec Empire that Cortés aimed to conquer was no primitive civilization. Tenochtitlán, built on an island in Lake Texcoco, was a marvel of engineering and urban planning.
Massive causeways connected the city to the mainland. Intricate canal systems transported goods and people throughout the metropolis.
Towering pyramids dominated the skyline, their steps stained with the blood of ritual sacrifice.
The Aztecs called themselves the Mexica, and they ruled through a combination of military might and religious terror.
Their empire stretched from coast to coast, built on the tribute extracted from conquered peoples. Warriors captured enemies not just to kill them, but to drag them to the great temples where their hearts would be cut out to nourish the gods.
Emperor Montezuma II ruled this empire with absolute authority. He lived in a palace with 100 rooms, served by thousands of servants. When he walked, nobles swept the ground before him and averted their eyes—to look directly at the emperor meant death.
Yet for all its power, the Aztec Empire contained the seeds of its own destruction. The tributary system created deep resentments among subject peoples.
Tribes across the empire chafed under Aztec rule, forced to provide warriors for endless wars and victims for bloody sacrifices.
The March Inland
Cortés understood that his tiny force could never defeat the Aztec Empire through direct assault.
Instead, he employed a strategy that would be copied by European conquerors for centuries: divide
and conquer.
As the Spanish marched inland from the coast, they encountered the Tlaxcalans, fierce warriors who
had long resisted Aztec domination. After initial battles that nearly destroyed the Spanish force, Cortés convinced the Tlaxcalans to join him. Suddenly, his 600 men became the core of an army thousands strong.
Other tributary peoples flocked to the Spanish banner. To them, Cortés represented hope—a chance to throw off the Aztec yoke.
The conquistador skillfully exploited these divisions, presenting himself as a liberator rather than a conqueror.
But Cortés possessed weapons beyond military alliance. Spanish steel was superior to Aztec obsidian. Horses, unknown in the Americas, struck terror into indigenous warriors.
Cannons and crossbows could kill at distances impossible with traditional weapons. Most importantly, Spanish armor could turn aside the razor-sharp obsidian blades that were the Aztecs’ primary weapons.
The God Who Walked Among Men
When Cortés and his expanding army approached Tenochtitlán in November 1519, Emperor Montezuma faced an impossible decision.
Aztec religious beliefs spoke of Quetzalcoatl, the feathered serpent god, who would one day return from the east. Some accounts suggest Montezuma believed Cortés might be this returning deity—or at least, he couldn’t risk the possibility that he wasn’t.
The emperor’s response was both hospitable and cautious. He sent magnificent gifts to the Spanish:
golden sun discs, elaborate featherwork, precious stones.
These treasures only inflamed Spanish greed. If these were mere gifts, what riches must await in the capital itself?
On November 8, 1519, Cortés and his men entered Tenochtitlán. They marched across the great causeway, past thousands of Aztec warriors, into the heart of an empire. The Spanish were stunned
by what they saw. Bernal Díaz del Castillo, one of Cortés’s soldiers, later wrote that the city seemed
like something from a dream, so magnificent it appeared unreal.
Montezuma welcomed the Spanish to his palace, offering them quarters within the royal compound.
For a brief moment, it seemed possible that the encounter might end peacefully. But Cortés had not come for diplomacy. Within days, he made his most audacious move yet: he took Montezuma hostage in his own palace.
The Prisoner Emperor
The capture of Montezuma was a masterpiece of psychological warfare. Cortés convinced the emperor to move into the Spanish quarters “for his own safety.” Once there, Montezuma found himself a prisoner, though one maintained in imperial luxury.
Through Montezuma, Cortés ruled the Aztec Empire by proxy. The emperor’s orders, dictated by his Spanish captors, were obeyed throughout the realm. Tribute continued to flow into Tenochtitlán, but now it enriched Spanish coffers. For months, this impossible arrangement held.
But the Spanish pushed too far. They demanded access to Aztec temples and began destroying religious idols, replacing them with Christian crosses. They melted down golden artifacts, reducing priceless works of art to mere bullion.
Most provocatively, they interrupted religious ceremonies and banned human sacrifice—the ritual that Aztecs believed kept the world in balance.
Primary Source: The Spanish Perspective
“We were astounded at the great marketplace and the crowds of people buying and selling… Every’ kind of merchandise such as can be met with in every land is for sale… There are streets where they sell only fowls, and others where they sell fabric-weavers’ implements… We were astounded at the orderliness and good government which we found everywhere.” — Hernán Cortés, Letter to Charles
La Noche Triste: The Night of Tears
The breaking point came in 1520. While Cortés was away dealing with a Spanish force sent to arrest him, his lieutenant Pedro de Alvarado massacred Aztec nobles during a religious festival.
The city erupted in fury.
When Cortés returned, he found Tenochtitlán in revolt. The Spanish were trapped in their palace compound, surrounded by hundreds of thousands of enraged Aztec warriors.
Montezuma, appearing before his people to urge calm, was struck by stones thrown by his own subjects. Whether he died
from these wounds or was killed by the Spanish remains disputed, but his death marked the end of
any hope for peaceful resolution.
On the night of June 30, 1520, the Spanish attempted to escape the city under cover of darkness. But
Aztec sentries spotted them, and war cries echoed across the lake. In the running battle that
followed—remembered in Spanish history as La Noche Triste (The Night of Tears)—hundreds of
Cortés’s men died. Many drowned in the lake, dragged down by the very gold they had looted. Of the
roughly 1,300 Spanish and allied forces that began the retreat, only about 500 survived.
Cortés himself barely escaped, wounded and humiliated. The conquest seemed over before it had
truly begun.
The Silent Killer
But as the Spanish retreated to lick their wounds, a more deadly invader was already at work in
Tenochtitlán. Smallpox, likely brought by an African slave in the Spanish expedition, began spreading
through the indigenous population.
The Aztecs had no immunity to Old World diseases. What began as isolated cases quickly became an
epidemic. The disease didn’t discriminate—it killed warriors and civilians, nobles and commoners,
priests and farmers. Entire communities were wiped out. Some estimates suggest that smallpox killed
more Aztecs than would die in all the military campaigns combined.
The epidemic devastated Aztec leadership. The new emperor, Cuitláhuac, died of smallpox just 80
days after taking power. His successor, Cuauhtémoc, inherited an empire in collapse—militarily
defeated, economically disrupted, and demographically catastrophic.
The disease gave Cortés the opportunity he needed. While the Aztecs struggled with plague, he
rebuilt his forces. More Spanish reinforcements arrived from Cuba. More importantly, indigenous
allies flocked to his banner as word spread that the mighty Aztec Empire was vulnerable.
The Final Siege
In 1521, Cortés returned to Lake Texcoco with a massive army. He now commanded not just Spanish
soldiers, but tens of thousands of indigenous warriors eager to destroy their former oppressors. The
Spanish had also built something unprecedented: a fleet of brigantines—small warships constructed
from timber carried over the mountains and assembled at the lake.
The siege of Tenochtitlán began in May 1521. It was not a battle but a systematic strangulation. The
Spanish cut the aqueducts that brought fresh water to the city. They blockaded the causeways to
prevent food from entering. Their brigantines controlled the lake, cutting off escape routes and supply
lines.
Day by day, the noose tightened. The Aztecs fought with desperate courage, but they were
outnumbered, outgunned, and weakened by disease and starvation. Spanish cannons collapsed
buildings. Allied indigenous warriors fought street by street through the city. The beautiful canals that
had been the city’s glory became clogged with bodies and debris.
By August 1521, Tenochtitlán was a ruin. The city’s population had been decimated by war, disease,
and famine. On August 13, 1521, Emperor Cuauhtémoc was captured trying to escape by canoe. The
Aztec Empire was finished.
What If: Alternative Histories
What if Montezuma had ordered the Spanish killed immediately upon their arrival? What if smallpox
had never reached the Americas? What if the Tlaxcalans had remained loyal to the Aztec Empire? Any
of these changes might have prevented the conquest—and altered the entire course of world history.
The Reckoning
The aftermath of the conquest was total. Tenochtitlán was razed to the ground, its stones used to
build Mexico City. Aztec codices—books containing the civilization’s history, science, and literature
were burned as works of the devil. The complex Aztec religion was banned, its priests killed or
converted. Spanish diseases continued to ravage the indigenous population for decades.
The gold and silver looted from the Aztec Empire flowed back to Spain, financing further conquests
and fueling European inflation. The encomienda system turned indigenous peoples into virtual slaves
on their own land. Spanish colonial rule would last for three centuries, fundamentally reshaping the
demographics, culture, and economy of Mexico.
Yet the conquest was not simply a story of European triumph and indigenous defeat. Many Aztec
traditions survived, blending with Spanish customs to create the distinctive Mexican culture that
exists today. The indigenous allies who helped defeat the Aztecs negotiated privileges that lasted
generations. Mestizaje—the mixing of Spanish and indigenous peoples—created entirely new
populations and identities.
Legacy of Blood and Gold
The Spanish conquest of the Aztec Empire remains one of history’s most dramatic military
achievements. With a force that could fit inside a modern sports stadium, Cortés toppled an empire
that had dominated Mesoamerica for over a century. The conquest demonstrated the power of superior technology, strategic alliances, and sheer audacity.
But it also revealed the devastating impact of disease on isolated populations and the destructive
potential of European colonial expansion. The conquest didn’t just end Aztec rule—it marked the birth
of colonial Latin America and began three centuries of exploitation that would shape the region’s development.
The story of Cortés and Montezuma has become legend, but the human cost should not be forgotten.
An empire that had ruled for centuries—built on sun, stone, and sacrifice—was erased in under two
years. The city’s canals ran with blood and sewage. The temples were razed, the gold looted, the
gods toppled.
In the end, 600 Spanish soldiers had conquered millions not through strength alone, but through a
combination of technological advantage, political cunning, indigenous allies, and biological warfare
they didn’t even understand they were waging. It was a conquest that changed two worlds forever.
