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, the Doctor lost the TARDIS to Kublai Khan in a game of backgammon. (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)
