The 1521 fall of Tenochtitlan began three centuries of profound, often violent, transformation. Key dimensions of colonizer-native interaction:
Smallpox, measles, influenza, typhus — no Indigenous immunity. Population collapse: ~90% decline in central Mexico by 1600 (from ~25M to ~1–2.5M). Social, spiritual, economic foundations shattered.
Franciscans, Dominicans, Augustinians led mass conversion. Temples destroyed; churches built on pyramids. Syncretism emerged: Virgin of Guadalupe (Tepeyac, 1531) fused Tonantzin (earth goddess) with Mary. Native scribes recorded Christian texts in Nahuatl (Latin script).
Encomenderos granted "commendation" of Indigenous communities — tribute (labor, goods) for "protection/Christianization." Brutal in mines (Zacatecas, Guanajuato), fields, obrajes (textile workshops). New Laws (1542) limited but didn't end it; repartimiento replaced.
Spanish men + Indigenous women → mestizo majority. Created new social hierarchy: peninsulares > criollos > mestizos > indígenas > negros. Mestizos became demographic/cultural core.
Reductions (congregaciones) concentrated dispersed populations for conversion/control. Taught Spanish, trades, agriculture. Basis for many modern towns.
Subsistence → export (silver, cochineal, cacao, hides). Indigenous labor drafted via repartimiento; markets monetized.
República de Españoles and República de Indios — parallel legal spheres. Over time, boundaries blurred; caste system (castas) formalized racial mixing.
The encounter was not monolithic — it varied by region, era, and actors. But its legacy defines Mexico's genetics, language, faith, food, and inequality today.