In early 1519, Hernán Cortés led an unauthorized expedition from Cuba toward the Mexican mainland, despite tensions with Cuba’s governor, Diego Velázquez. This decision set up a conflict over who had legal authority to claim and govern new lands, which shaped Cortés’s next steps in Mexico.
After reaching the Gulf region, Cortés fought Maya forces near the Grijalva River in what is often called the Battle of Centla. Soon after, the Spaniards received Malintzin (also known as Doña Marina/La Malinche), who became a crucial interpreter and political go-between, helping Cortés negotiate alliances and understand local rivalries.
Cortés founded the settlement of Villa Rica de la Vera Cruz on the coast, creating a town council (cabildo) under Spanish law. This helped him claim he was acting directly for the Spanish Crown rather than obeying the governor of Cuba, strengthening his political position to continue inland.
After fighting and negotiating in central Mexico, Cortés secured an alliance with Tlaxcala, a powerful rival of the Mexica (Aztec) state. The Tlaxcalans supplied large numbers of warriors and local knowledge, turning the Spanish expedition into a coalition campaign rather than a purely European conquest.
In Cholula, a major religious and political center, Cortés’s forces carried out a large-scale killing in October 1519. The violence intimidated other cities and demonstrated what Spanish-aligned forces could do, but it also deepened fear and hostility toward the newcomers.
Cortés and his Indigenous allies entered the Mexica capital of Tenochtitlan and met the ruler Moctezuma II. The Spaniards were struck by the city’s scale and organization, and they quickly realized that controlling the ruler could be a path to controlling the empire’s tribute and political decisions.
By mid-November 1519, Moctezuma II was effectively held under Spanish control in his own capital. This hostage-taking strategy aimed to reduce immediate resistance and channel imperial authority through Spanish demands, but it also increased tension in Tenochtitlan and undermined Moctezuma’s legitimacy.
While Cortés was away from the capital, Spaniards under Pedro de Alvarado killed unarmed Mexica elites during the festival of Toxcatl. This event helped turn a tense occupation into a broader uprising, making continued Spanish control of the city far more difficult.
On the night of June 30 to July 1, 1520, Cortés and his forces attempted to escape Tenochtitlan under attack. Many Spaniards and allies were killed during the retreat, and the loss forced Cortés to rebuild his coalition and strategy before attempting to take the city again.
About a week after escaping the capital, Cortés’s battered force fought a major battle at Otumba against pursuing Mexica troops. The Spanish-Tlaxcalan victory helped the survivors reach friendly territory, preserving the core of the expedition for a renewed campaign.
In late 1520, a smallpox epidemic spread through the Valley of Mexico, including Tenochtitlan. The disease killed many people who had no prior immunity and also contributed to political and military disruption, including the death of the Mexica leader Cuitláhuac.
In spring 1521, Cortés prepared a naval force of brigantines (small sailing-and-rowing warships) to fight on Lake Texcoco around the island city. Launching these vessels helped the Spanish-led coalition challenge Mexica control of canals and canoes, tightening the siege’s blockade and supporting attacks along the causeways.
By late May 1521, Cortés and a large coalition of Indigenous allies began the final siege of Tenochtitlan, attacking along the causeways and controlling the lake with brigantines. The siege aimed to cut food and water supplies and to wear down defenders through repeated assaults, shifting the conflict into a prolonged battle for the city itself.
After months of fighting, famine, and disease, Tenochtitlan surrendered on August 13, 1521, and the last ruler, Cuauhtémoc, was captured while attempting to escape. The city’s fall ended organized Mexica control of the imperial capital and marked a decisive turning point toward Spanish colonial rule in central Mexico.
Spanish conquest of the Aztec Empire (1519–1521)