What happened
Teotihuacan emerged as a religious centre in the first century CE. It grew into an eight-square-mile city housing ~100,000 people — 80–90% of the Valley of Mexico’s population. Major monuments were built continuously from ~100 BCE to ~250 CE. Around 550 CE, its central monuments were systematically burned. The city persisted at reduced scale until the 7th or 8th century CE.
How we know it
Archaeological evidence confirms construction of the Pyramid of the Sun and Pyramid of the Moon. Radiocarbon dating and stratigraphy support continuous monumental building from ~100 BCE to ~250 CE. Population estimates derive from settlement surveys and spatial analysis of the eight-square-mile urban footprint. The 550 CE burning event is attested by widespread ash layers and fire-damaged stonework in major civic-religious structures.
Why it went that way
The material gives no cause for decline or burning. No source names perpetrators, motives, or environmental stressors. The record shows only that systematic burning preceded terminal decline — not that it caused it. The gap between event and explanation remains unbridgeable with current evidence.
What is still contested
Who ruled Teotihuacan is unknown — no royal tombs, named rulers, or deciphered inscriptions exist. Whether the 550 CE burning was internal revolt, external attack, or ritual decommissioning is unresolved. The cause of final abandonment is unattested. The meaning of its name — not recorded in pre-Columbian sources — is inferred only from later Nahuatl usage.
What it changed
Teotihuacan set precedents for monumental urban planning across Mesoamerica: the grid-aligned Avenue of the Dead, multi-family apartment compounds, and state-sponsored mural programmes. Its artistic motifs, ceramic styles, and religious symbols spread to Maya cities like Tikal and Copán. Its model of non-hereditary, possibly collective authority influenced later polities — though no source states this directly.
Is it worth your time
Yes. Teotihuacan reshaped Mesoamerican urbanism, ritual practice, and political imagination for centuries — but its internal governance, collapse triggers, and even its name remain unknown. It forces a reckoning with what archaeology can and cannot say about power without texts.
