Siege of Tenochtitlán — Destruction of the Aztec Capital
The siege of Tenochtitlán (26 May – 13 August 1521) was the culmination of the Spanish conquest of Mexico. Cortés had been driven from the city on the Noche Triste ('Sad Night') of 30 June 1520, losing approximately a third of his men. He spent the following months rebuilding his force, most critically by constructing thirteen brigantines (small sailing warships) that could be transported over the mountains in pieces and launched on Lake Texcoco. The military situation confronting Cortés was extraordinary: Tenochtitlán was an island city of perhaps 200,000–300,000 inhabitants, connected to the mainland by three causeways. Its lake position had made it militarily invulnerable to all previous challengers. Cortés's solution was the brigantines — which controlled the lake, intercepting supply canoes and covering troop movements on the causeways — combined with his massive indigenous alliance (Tlaxcalans, Texcocans, and dozens of other polities who had suffered under Aztec tributary demands). The siege had three phases: control of the lake (achieved by late May), systematic advance down the three causeways destroying buildings as the army advanced to prevent ambush retreats, and the final destruction of Tlatelolco (the commercial district) in early August. The Mexica defenders, led by Cuauhtémoc (who had assumed the throne after Moctezuma II's death), fought with exceptional tenacity — Cortés himself noted that 'they fight much more fiercely and with greater skill than those of any city we have taken.' Smallpox had arrived in 1520 and killed vast numbers of the population — including the emperor Cuitláhuac — during the siege's preparation period. The disease that Cortés's forces transmitted unknowingly may have done more to weaken Tenochtitlán than any military action. Cuauhtémoc was captured attempting to escape by canoe on 13 August 1521. Tenochtitlán was razed; the rubble was used to fill in the lake. Mexico City was built directly over the site — the Aztec foundations remain beneath the colonial and modern city. An estimated 100,000–240,000 Mexica were killed during the siege; the population of central Mexico collapsed from perhaps 25 million to under 2 million over the following century.
- Year: 1521 CE
- Category: Military
