Spanish Conquest of the Aztec Empire (1519-1521): Cortés

The Spanish conquest of the Aztec Empire (1519-1521) was the campaign in which the conquistador Hernán Cortés, a few hundred Spaniards and tens of thousands of Indigenous allies destroyed the power of the Mexica of Tenochtitlan, the dominant state in central Mexico. It ended with the fall of Tenochtitlan on 13 August 1521, after a siege made worse by a devastating smallpox epidemic. The conquest created the Spanish colony of New Spain and is one of the most consequential and most mythologised events in the history of the Americas.

Background: the Aztec Empire in 1519

The empire usually called “Aztec” was a network of tribute-paying city-states dominated by the Aztec Triple Alliance of Tenochtitlan, Texcoco and Tlacopan, formed in 1428. By 1519 the Mexica city of Tenochtitlan was the senior partner. Built on an island in Lake Texcoco and linked to the shore by causeways, it was one of the largest cities in the world, with a population often estimated at 200,000 or more.

The empire collected tribute from hundreds of towns but did not directly govern them, and it had powerful enemies. The most important was Tlaxcala, an independent confederation east of the Valley of Mexico that had resisted Mexica pressure for decades. Many subject towns also resented heavy tribute demands and the taking of captives for sacrifice.

On the Spanish side, conquistadors had settled Hispaniola and Cuba, and two earlier expeditions from Cuba (1517 and 1518) had brought back news of rich societies on the mainland. The governor of Cuba, Diego Velázquez, chose Hernán Cortés to lead a third expedition, then tried to cancel the commission. Cortés sailed anyway.

Landing and the march inland (1519)

Cortés left Cuba in February 1519 with about 11 ships, some 500 soldiers, about 100 sailors, 16 horses and a few cannon. On Cozumel he picked up Gerónimo de Aguilar, a Spaniard shipwrecked years earlier who spoke Maya. After a battle at Potonchán in Tabasco, local lords gave the Spaniards 20 women, among them a Nahuatl-speaking woman later known as Malintzin or Doña Marina. Together, she and Aguilar became the expedition’s interpreters.

In April 1519 the fleet reached the Gulf coast near today’s Veracruz. To free himself from Velázquez’s authority, Cortés founded a town, Villa Rica de la Vera Cruz, whose council named him its captain and appealed directly to King Charles. He won the alliance of the Totonacs of Cempoala, who were unhappy Mexica tributaries, and then deliberately ran most of his ships aground so that his men could not turn back to Cuba.

In August the Spaniards marched inland. In September they fought several hard battles against Tlaxcala, then made peace and formed the alliance that would decide the war. In October, at Cholula, a city allied to the Mexica, the Spaniards and Tlaxcalans killed thousands of people in the Cholula massacre, an event whose causes are still debated.

Tenochtitlan and the captive emperor

On 8 November 1519 Cortés entered Tenochtitlan along the southern causeway and was received by the huey tlatoani (great ruler) Moctezuma II with great ceremony. The Spaniards were lodged in the palace of Moctezuma’s father, Axayacatl. Within about a week, fearing a trap, Cortés took Moctezuma into custody and began to rule through him.

For several months an uneasy balance held. In spring 1520 Velázquez sent a large force under Pánfilo de Narváez to arrest Cortés. Cortés left Pedro de Alvarado in charge of the city, marched to the coast, defeated Narváez in a night attack at Cempoala in late May, and added most of his men to his own army.

Revolt, retreat and smallpox (1520)

During Cortés’s absence, Alvarado’s men attacked Mexica nobles celebrating the festival of Toxcatl in the main temple precinct and killed many of them. The city rose in revolt. Cortés returned in June to find the Spaniards besieged. Moctezuma, brought out to calm the crowds, died in late June 1520; how he died is still disputed.

On the night of 30 June to 1 July 1520, the Spaniards and their allies tried to slip out of the city along the Tlacopan causeway. Discovered, they were attacked from canoes and lost hundreds of Spaniards and probably thousands of allies, along with much of their treasure, in the episode known as La Noche Triste (“the sad night”). A week later the survivors won a desperate battle at Otumba and reached safety in Tlaxcala, whose leaders kept the alliance alive.

Meanwhile smallpox, brought to the mainland in 1520, swept through central Mexico. Moctezuma’s successor Cuitláhuac died of the disease after a reign of about 80 days, and his cousin Cuauhtémoc became ruler early in 1521.

The siege and fall of Tenochtitlan (1521)

Cortés rebuilt his army with Spanish reinforcements and many more Indigenous allies. He secured the towns around the lake, won over a faction in Texcoco, and had 13 brigantines (small sailing warships) built in parts by the shipwright Martín López, carried overland and launched on Lake Texcoco in April 1521.

The siege began in late May 1521. Spanish and allied forces cut the aqueduct from Chapultepec that brought fresh water, blockaded the causeways and used the brigantines to control the lake. The Mexica defended the city street by street for nearly three months, despite hunger, disease and heavy losses. Spanish and allied troops destroyed buildings as they advanced to deny cover to the defenders.

On 13 August 1521 Cuauhtémoc was captured in a canoe trying to escape, and resistance ended. Much of the city lay in ruins. The final stage is told in more detail in Fall of Tenochtitlan.

Key people

• Hernán Cortés (1485-1547): Spanish conquistador who led the expedition, organised the alliances and directed the siege.
• Moctezuma II (c. 1466-1520): Ruler of Tenochtitlan from 1502, who received the Spaniards and died in their custody.
• Cuitláhuac (died 1520): Moctezuma’s brother and successor, who led the expulsion of the Spaniards and died of smallpox.
• Cuauhtémoc (c. 1495-1525): Last Mexica ruler, who defended the city in 1521. He was executed on Cortés’s orders in 1525 during an expedition to Honduras.
• Malintzin (La Malinche): Nahua woman who served as Cortés’s interpreter and adviser.
• Xicotencatl the Elder and Maxixcatzin: Leading lords of Tlaxcala who backed the alliance with the Spaniards.

Why the Mexica lost

Historians stress a combination of causes rather than one decisive advantage:

• Indigenous allies: Tlaxcala, Huexotzinco, factions of Texcoco and many other towns provided most of the soldiers, porters and food. Their decision turned a Spanish expedition into an Indigenous civil war against Mexica dominance.
• Disease: Smallpox killed a large share of the population, including Cuitláhuac and many experienced commanders, just before the siege.
• Technology and tactics: Steel swords, armour, crossbows, firearms, horses and the lake brigantines gave the Spaniards local advantages, though not overwhelming ones.
• Political structure: The empire’s reliance on tribute rather than direct rule meant subject towns had little reason to defend it.

Consequences

The Spanish built Mexico City on the ruins of Tenochtitlan, and in 1522 Charles V appointed Cortés governor of New Spain. Indigenous towns were assigned to Spanish settlers under the encomienda system, which demanded tribute and labour. Franciscan friars arrived in 1524 and began mass conversions, while temples and books were destroyed.

Cortés himself did not keep power for long. The crown, wary of an overmighty conquistador, sent royal officials and later an audiencia (high court) to govern, and in 1535 appointed the first viceroy of New Spain, Antonio de Mendoza. Cortés received the title Marquis of the Valley of Oaxaca and large estates, but spent his last years in disputes with the crown and died in Spain in 1547.

From Mexico City, Spanish expeditions spread outwards over the following decades, to the Maya lands of Guatemala and Yucatán, to western Mexico and later far to the north. Silver discovered in the mid-16th century at Zacatecas and other mines made New Spain one of the richest parts of the Spanish Empire.

The allies who had made victory possible received some privileges. Tlaxcala, for example, kept a degree of self-government and tax exemptions. However, all Indigenous peoples of central Mexico soon came under colonial rule, and repeated epidemics in the 16th century caused a population collapse that many scholars estimate at well over half, and possibly up to 90 percent, by 1600.

Myths and facts

• Myth: A few hundred Spaniards conquered an empire. The Spanish forces were small, but they fought alongside tens of thousands of Indigenous warriors who had their own reasons to fight the Mexica.
• Myth: The Mexica believed Cortés was the god Quetzalcoatl. This story appears in accounts written years later and is now widely doubted.
• Myth: Cortés burned his ships. He had them run aground and stripped, not set on fire.

Timeline

• 1519, February: Cortés sails from Cuba against the governor’s wishes.
• 1519, April: The expedition lands near today’s Veracruz.
• 1519, September: Battles with Tlaxcala end in an alliance.
• 1519, October: The Cholula massacre.
• 1519, 8 November: Cortés enters Tenochtitlan and meets Moctezuma II.
• 1520, May: Cortés defeats Narváez; Alvarado’s men attack the Toxcatl festival.
• 1520, late June: Moctezuma dies in Spanish custody.
• 1520, 30 June - 1 July: La Noche Triste; the Spaniards flee the city.
• 1521, late May: The siege of Tenochtitlan begins.
• 1521, 13 August: Cuauhtémoc is captured and the city falls.

Why it matters

The conquest of the Aztec Empire ended the most powerful state in Mesoamerica and began three centuries of Spanish rule in Mexico. It reshaped the population, religion, language and landscape of the region and became a model for later Spanish conquests, including that of the Inca Empire.