1428
Triple Alliance Overthrows Azcapotzalco
Tenochtitlan, Texcoco, and Tlacopan combined armies and crushed the Tepanec overlord who had dominated the Valley of Mexico. The three cities split the spoils and declared themselves eternal allies. The empire that Cortes would meet ninety years later was born in this single rainy-season campaign. The victory transformed Tenochtitlan from a tributary island into central Mexico's dominant military power, controlling a basin of two million people.
Ulugh Beg's Samarkand Observatory Built
Timur's astronomer grandson erected a three-story brick sextant with a radius of forty meters on a hill outside Samarkand. Over two decades his team catalogued a thousand stars with unprecedented accuracy and computed the sidereal year to within a minute. European astronomers would quietly crib his tables for two centuries.
Le Loi Founds the Later Le Dynasty
With the last Ming garrisons retreating north, the rebel leader assumed the throne as Emperor Le Thai To of Dai Viet. He issued a famous proclamation declaring Vietnam's cultural independence from China, paid careful tribute to Beijing anyway, and set about rebuilding a kingdom that would last three centuries. His Great Proclamation declared that north and south had different customs, establishing cultural independence as the bedrock of Vietnamese identity.
Aztecs Burn Historical Codices
Itzcoatl and his advisor Tlacaelel ordered the destruction of older painted histories and the production of new ones centered on Mexica glory. The past was literally reissued. It is why modern archaeologists, sifting through pre-Triple-Alliance strata, find so little continuous historical memory in Mexica sources. The destruction ensured subsequent accounts were filtered through Triple Alliance ideology, making earlier Aztec political life nearly impossible to reconstruct.