Triple Alliance power peaked just as Cortés arrived
From about 1300 to 1521, Nahuatl-speaking peoples of central Mexico built a civilisation of altepetl city-states. Three of them—Tenochtitlan, Texcoco, and Tlacopan—forged an empire that ruled by clients and marriage, not garrisons, and reached its widest reach in 1519, the year Spanish invaders landed.
Shared Mesoamerican habits—maize farming, noble pipiltin versus commoner macehualtin, a crowded pantheon, interlocking calendars—knit the Valley of Mexico together. The Mexica arrived late, planting Tenochtitlan on awkward islets in Lake Texcoco. Their Triple Alliance, formed in 1427, soon made Texcoco and Tlacopan junior partners while Tenochtitlan set the pace, projecting power through trade, conquest, friendly puppet rulers, and dynastic marriages rather than carpeting the map with forts.
That hegemonic system hit maximum extent in 1519, immediately before Hernán Cortés arrived and allied with cities that hated Mexica dominance. Tenochtitlan fell on 13 August 1521; emperor Cuauhtémoc was captured; Mexico City rose on the ruins as colonisation folded the region into Spain’s empire. What we know comes from Templo Mayor digs, Indigenous books, conquistador eyewitnesses, and later bilingual works such as the Florentine Codex, compiled by the Franciscan Bernardino de Sahagún with Nahua informants.
Subject cities paid taxes to the ruler called the Huey Tlatoani, in an arrangement meant to limit contact and trade between outlying provinces so that each stayed tied to the centre. After 1521 the Spanish kept that local scaffolding, governing the Indigenous population through native nobles in each city-state. One of the richest colonial records, the Codex Mendoza, was possibly commissioned by the first viceroy to show the crown which polities the alliance had conquered and what they rendered.
Even the word “Aztec” is a later coinage. Aztēcatl meant a person from Aztlán, a mythical homeland claimed by several groups, and no people used it for themselves; the Mexica called themselves Mēxihcah or Tenochcah. Alexander von Humboldt popularised the collective label in 1810 and William Prescott's 1843 history of the conquest spread it. Scholars still object: Robert Barlow preferred Culhua-Mexica, and Pedro Carrasco the Tenochca Empire.
Source: Aztecs
