The Mexica established Tenochtitlan on islands in Lake Texcoco around this year, beginning the growth of a planned island-capital linked to the mainland by causeways and expanded through land-making and chinampa agriculture.
A dissident Mexica group founded Mexico-Tlatelolco on the northern part of the same island system, creating a paired urban complex in which Tlatelolco became especially important for regional commerce and its major market.
With Acamapichtli’s selection as the first tlatoani (dynastic ruler) of Tenochtitlan, the city consolidated political legitimacy through elite alliances and established a royal line that shaped later imperial expansion.
Tenochtitlan allied with Texcoco and Tlacopan to form the Triple Alliance, a political-military framework that underpinned rapid expansion and centralized tribute flows that enriched the capital and its urban system.
A major hydraulic program to bring spring water from Chapultepec to Tenochtitlan began during the mid-15th century, reflecting the scale of water-management needs in a dense island metropolis.
The Chapultepec aqueduct’s completion brought a more reliable freshwater supply into the city, supporting population density and urban provisioning while showcasing sophisticated state-coordinated engineering.
Conflict between Tenochtitlan and Tlatelolco ended with Tenochtitlan’s victory, tightening political control over the island’s northern city and its highly significant marketplace within the broader capital system.
During Ahuitzotl’s reign, the Templo Mayor—the ceremonial core of Tenochtitlan—was rebuilt and rededicated in a major state ritual cycle, reinforcing the capital’s role as the religious and political center of the imperial urban network.
Moctezuma II’s accession marked the last long reign of a fully independent Mexica ruler; the empire reached its greatest territorial extent as the capital’s tribute and administrative reach intensified.
Hernán Cortés and his forces (with Indigenous allies) entered Tenochtitlan and met Moctezuma II, initiating a crisis in the capital that quickly shifted from diplomacy and display to coercion and armed conflict.
After escalating violence and uprising in the capital, Cortés and his forces attempted a nighttime withdrawal and were attacked; the episode became known as La Noche Triste, demonstrating that control of the island-city depended on causeways, alliances, and urban logistics as much as battlefield tactics.
A smallpox epidemic struck the Basin of Mexico, including Tenochtitlan, sharply weakening the city’s population and leadership at a pivotal moment and undermining the capital’s ability to sustain defense and provisioning.
Cuauhtémoc’s coronation placed military leadership in the hands of the last Mexica ruler during the closing phase of the conflict, as the capital faced siege conditions and shrinking alliances.
A Spanish–Indigenous coalition besieged the capital, fought through its causeways and canals, and captured the city; Cuauhtémoc was taken prisoner and Tenochtitlan’s urban core was devastated, enabling the transformation of the capital zone into the nucleus of colonial Mexico City.
Tenochtitlan and the Aztec Urban System (c. 1325–1521 CE)
