Who they were
Great Khan of the Mongols from 1260, he proclaimed the Yuan dynasty in 1271 and fixed its capital at Dadu, modern Beijing.
What they did
He completed the conquest of the Southern Song by 1279, governing with Chinese-style institutions while keeping Mongol and other non-Han elites on top. His two invasions of Japan, in 1274 and 1281, failed — the second wrecked by a typhoon the Japanese called kamikaze. His court welcomed foreign merchants and travelers; Marco Polo’s account claims years in his service.
Legacy
His reign began Beijing’s rise as imperial capital and made all-China rule by a conquest dynasty a repeatable pattern, later followed by the Qing.