Genghis Khan

Genghis Khan was a Mongol military leader and the grandfather of Kublai Khan. (TV: "Assassin at Peking") Temulen Khatun was his docile and subservient sister. (PROSE: A Hundred Words from a Civil War)

According to one account, the First Doctor once encountered Genghis Khan. (PROSE: Time and Relative) According to another account, the First Doctor claimed to Genghis' grandson that he had heard of Genghis but hadn't met him. (TV: "Assassin at Peking")

The Seventh Doctor claimed to have delivered Genghis Khan, describing him as "a sweet baby." (PROSE: Tragedy Day)

When claimed he wanted to rule people "for their own good", the Third Doctor wondered if he had heard Adolf Hitler or Genghis Khan say the same thing. (TV: The Dæmons)

once lied and told Chang Lee that the Doctor had been Genghis Khan in one incarnation. (TV: Doctor Who)

The Doctor's TARDIS once withstood an attack from the hordes of the Genghis Khan, as recounted by the Sixth (AUDIO: City of Spires) and Ninth Doctors. (TV: Rose)

The Eleventh Doctor was uncertain if it had been Al Capone or Genghis Khan who had told him that villains wanted records of exactly how bad they'd been. (PROSE: Borrowed Time)

Invalid sources
The Cybus Industries website, which tied into Rise of the Cybermen and The Age of Steel, featured an interview with John Lumic, the creator of the Cybermen of Pete's World. When asked the which four people he would invite to dinner, Lumic listed Genghis Khan along with Niccolo Machiavelli and Adolf Hitler, citing all three as having "got what they wanted in spite of the little people".