Kublai Khan was an emperor of the Mongols and the grandson of Genghis Khan.
In 1289, the First Doctor, Ian Chesterton, Barbara Wright and Susan Foreman met Kublai Khan. During this adventure, Marco Polo tried to claim the TARDIS for the Khan. In Peking, The Doctor lost the TARDIS to Kublai Khan in a game of backgammon, a game the Khan’s wife claimed aggravated his gout. The Doctor made Polo aware that the war lord Tegana was working against the Khan, and Polo stopped Tegana from assassinating the Khan. (Marco Polo)