Kublai Khan
From Tardis Wiki, the free Doctor Who reference
Kublai Khan, Khubilai Khan or "the last of the Great Khans", was a 13th century emperor of the Mongols and an emperor of China. (DW: Marco Polo)
He was the grandson of Genghis Khan, whom the Seventh Doctor had delivered (NA: Tragedy Day) and whom the First Doctor had previously claimed to have encountered as an adult (TN: Time and Relative).
In 1289, he met the First Doctor, Ian Chesterton, Barbara Wright and Susan Foreman. (DW: Marco Polo)