Kublai Khan
Kublai Khan, Khubilai Khan or "the last of the Great Khans", was a 13th century emperor of the Mongols and an emperor of China. (TV: Marco Polo)
He was the grandson of Genghis Khan, whom the Seventh Doctor had delivered (PROSE: Tragedy Day) and whom the First Doctor had previously claimed to have encountered as an adult. (PROSE: Time and Relative)
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. (TV: Marco Polo)
The Second Doctor told his companion Jamie McCrimmon about losing the TARDIS to Kublai Khan. (AUDIO: House of Cards)
The Sixth Doctor told his companion Evelyn Smythe that he had dined with Kublai Khan. (AUDIO: Project: Twilight)