Genghis Khan's grandson, who completed the Mongol conquest of China, founded the Yuan dynasty in 1271, and made himself emperor of one of the richest realms on earth -- claiming the title of Great Khan while ruling China as Son of Heaven, a nomad warlord's heir who put on Chinese robes, built a capital where Beijing now stands, opened Eurasia to the trade and travelers of the Mongol peace, and then spent heavily on failed overseas and southern campaigns, especially the Japan invasions of 1274 and 1281, where storms helped wreck the fleets.
He was a nomad's grandson who made himself a Chinese emperor. Kublai Khan inherited a share of the largest land empire ever built, then did something none of his line had managed: he conquered the wealthy, sophisticated south of China and ruled it from a throne. In 1271 he gave his dynasty a Chinese name, the Yuan, and built a new capital where Beijing stands today. To his own Mongol court he remained the Great Khan, though his authority over the western khanates was increasingly more claim than reality. To his Chinese subjects he was the Son of Heaven. A Venetian named Marco Polo came to his court and went home with tales of a splendor Europe could barely believe, of a city called Xanadu and a land called Cathay. Yet the same emperor twice sent vast fleets against Japan, and twice the sea swallowed them in storms the Japanese called the divine wind. He ruled one of the world’s richest realms and could not conquer Japan’s islands. The empire he made in China outlasted him by less than a century.