Spanish conquest of the Aztec Empire

In little more than two years, from early 1519 to August 1521, a small Spanish force led by Hernán Cortés, together with tens of thousands of Indigenous allies, brought down the Aztec Empire, the most powerful state in Mesoamerica. Their success owed as much to the alliance with the Aztecs' enemies and subjects, above all Tlaxcala, and to an epidemic of smallpox as to Spanish steel, horses and guns. The conquest began three centuries of Spanish rule in what became New Spain.

The Aztec Triple Alliance, formed in 1428 by Tenochtitlan, Texcoco and Tlacopan, ruled much of central Mexico through tribute rather than direct control, and many subject cities resented it. After Spanish voyages along the coast in 1517 and 1518, the governor of Cuba, Diego Velázquez, chose Cortés to lead a third expedition, then tried to cancel it. Cortés sailed anyway on 10 February 1519 with 11 ships and about 630 men, technically a mutineer. On the coast he gained two vital interpreters: Gerónimo de Aguilar, a shipwrecked Spaniard who spoke Maya, and an enslaved Nahua woman known as Malintzin or Doña Marina, who spoke both Maya and Nahuatl.

Landing near present-day Veracruz in April 1519, Cortés founded a town whose council made him its captain-general, freeing him from Velázquez's authority, and scuttled his ships to prevent desertion. He persuaded the Totonacs of Cempoala to defy the Aztecs. Moving inland, he fought the Tlaxcalans for about eighteen days before they made peace and became his most important allies. In October his forces massacred thousands of people in Cholula, for reasons the surviving accounts dispute.

On 8 November 1519 the emperor Moctezuma II received Cortés in his island capital, and the Spaniards were lodged in a palace. Cortés later claimed to have taken Moctezuma captive soon after, though modern scholars doubt the timing. In spring 1520 Velázquez sent Pánfilo de Narváez with a larger force to arrest Cortés; Cortés defeated him in a night attack at Cempoala and won most of his men over. Meanwhile Pedro de Alvarado, left in charge of the city, attacked Aztec nobles at a religious festival in the Great Temple, provoking a general uprising.

When Cortés returned, the Spaniards were besieged. Moctezuma died in disputed circumstances, killed according to some accounts by stones thrown by his own people and according to others by the Spaniards. On the night of 30 June 1520 the Spaniards and their allies tried to slip out along a causeway and were cut to pieces; estimates of Spanish dead range from a few hundred to around a thousand, along with many Tlaxcalans. The survivors fought off a pursuing army at Otumba in July and found refuge in Tlaxcala.

That autumn smallpox swept through central Mexico, killing millions according to some estimates, among them Moctezuma's successor Cuitláhuac. Cortés rebuilt his forces with new Spanish arrivals and Indigenous allies, made Texcoco his base and had thirteen brigantines built to control the lake. The siege of the capital began in May 1521 and ended with the capture of the last emperor, Cuauhtémoc, on 13 August, events described in more detail in the fall of Tenochtitlan.

Mexico City was built on the ruins, and in 1522 Charles V named Cortés captain-general of New Spain. Franciscan missionaries arrived in 1524, Cuauhtémoc was executed in 1525, and the Purépecha kingdom of Michoacán came under Spanish control after 1522. In 1535 the crown appointed a viceroy. Many former Aztec subject cities kept their own ruling families and internal structures, and colonial government relied heavily on the Indigenous nobility.

Our 1500 map shows the Aztec Empire at its height, and the 1530 map shows central Mexico under Spanish rule.