1427
Itzcoatl Becomes Aztec Tlatoani
The fourth ruler of Tenochtitlan, an illegitimate son of an earlier king, took the turquoise crown and immediately began rewriting history, literally. He ordered the old codices burned and new ones painted. The Mexica, he insisted, had always been a chosen people. The Aztec Empire effectively begins with him. His adviser Tlacaelel redesigned the state religion around mass human sacrifice and the cult of Huitzilopochtli, the sun god.
Masolino and Masaccio Paint Together
Two painters shared the Brancacci Chapel commission in Florence, the older Masolino using traditional Gothic rhythms and the younger Masaccio inventing a new solidity of flesh and gravity. Their side-by-side panels staged a pedagogical argument. Within months Masaccio was dead at twenty-seven, and Florentine art had quietly crossed a threshold.
Aztec Chinampas Expansion in Lake Texcoco
Engineers of the Triple Alliance expanded the ingenious system of floating gardens in the shallow waters of Lake Texcoco, creating artificial agricultural islands of woven reeds, lake mud, and anchored vegetation that produced multiple harvests per year without exhausting the soil. The chinampas fed a capital of over two hundred thousand people and represented one of the most productive and sustainable agricultural systems anywhere in the pre-industrial world.