1420
Forbidden City Completed in Beijing
After fourteen years of labor by a million conscripts, the Yongle Emperor's new northern palace opened its vermilion gates. Nine thousand rooms, roofs of imperial yellow tile, courtyards calibrated to cosmological axis. The Ming court moved from Nanjing and China's center of gravity shifted permanently toward the steppe. Its north-south axis, aligned with the Pole Star, expressed the emperor's cosmological role as mediator between heaven and earth.
Brunelleschi Begins the Florence Cathedral Dome
Nobody in Europe had built a masonry dome that wide in a thousand years. Brunelleschi, a goldsmith with no architectural training, designed a double shell raised without scaffolding, laid brick in herringbone patterns, and invented new hoists powered by oxen. Florence held its breath for sixteen years. The completed dome remains the largest masonry dome ever built and one of the supreme achievements of Renaissance engineering.
Treaty of Troyes
Henry V married Catherine of Valois and was named heir to the French throne, disinheriting the Dauphin. It seemed the war was finally over. Both kings would be dead within two years, and a sickly English toddler and a Dauphin hiding at Chinon would inherit a ruined kingdom in halves.
Beijing Replaces Nanjing as Capital
The Yongle Emperor formally declared Beijing the northern capital, relegating Nanjing to secondary status. Grain barges streamed up the Grand Canal to feed a city of a million in the face of the Mongol steppe. The Ming center of gravity had swung permanently north, toward its most dangerous frontier. The relocation required renovating the Grand Canal to carry millions of shi of tribute rice, rivaling the Forbidden City's own construction.
Hussite Wars Begin
Bohemian Hussites under Jan Zizka built wagon-forts, drilled peasant infantry, and defeated successive crusader armies sent by Sigismund. Zizka, blind in one eye and then both, won every battle he fought. His tactics influenced European warfare for a century. Bohemia had become, briefly, a military laboratory for social revolution. Their wagon-fort tactics and early hand cannons anticipated the combined-arms methods that dominated European warfare a century later.