As Great Khan of the Mongol Empire, Kublai reigned from 1260 to 1294 over one fifth of the world’s inhabited land area.
He was the grandson of Genghis Khan, the founder and first great leader of the Mongol Empire.
If one counts the Mongol Empire at that time as a whole, his realm reached from the Pacific to the Black Sea, from Siberia to modern day Afghanistan.
In 1271, Kublai founded the Yuan dynasty in modern day Beijing, which ruled over present-day Mongolia, China, Korea, and some adjacent areas, and assumed the role of Emperor of China.
By 1279, the Yuan forces had overcome the last resistance of the Southern Song dynasty, making Kublai the first foreign conqueror to rule all of China.
As the first Yuan emperor he ruled until his death in 1294.
His dynasty, the “Great Yuan” would last until 1368.
The West knew Genghis Khan through the writing of the Venetian merchant Marco Polo who visited his court in about 1274.