Mao Tse-Tung was a Chairman of China in the 20th century. During his reign he commited acts of brutality such as the annexation of Tibet and 'reeducation' camps. One camp, the Chairman Mao Ideal Collective, was named after him. (PROSE: Revolution Man)
Sometime in the Doctor's first or second incarnation, he encountered Mao. During the preparations for the World Peace Conference, the Third Doctor mentioned to the Chinese delegate Fu Peng that he remembered having a conversation in Hokkien with Mao, at which time the Chairman allowed the Doctor to call him by his personal name, "Tse-Tung". (TV: The Mind of Evil) Years later, he mentioned this to Sarah Jane Smith as well. (PROSE: Interference - Book One)
The Seventh Doctor would claim he'd been on Mao's Long March. (PROSE: Shadowmind) The Eighth Doctor just remarked he was on friendly terms with the man before his rise to power. (PROSE: Revolution Man)
In a parallel universe where the Third Doctor didn't land on Earth until 1997, when the Master sneered how Mao had spoken "ever so highly of you", the Doctor defensively said he'd only met Mao when he was just a librarian. (AUDIO: Sympathy for the Devil)
Behind the scenes
- The Discontinuity Guide, DWM 451, and Jonathan Clements, the writer of Sympathy, have all remarked that it's odd for the Doctor to have been on friendly terms with Mao, a notoriously brutal dictator (though Alan Barnes noted that the Doctor never outright says they're friends. (DWM 451) Clements noted the Cultural Revolution was going on at the very time the episode was written and aired, although he also notes that the reality of conditions under Mao were not widely known in the West when The Mind of Evil was shown in 1971..
- The fact that the Doctor suggests he spoke Hokkien with Mao suggests a difference between the real world and the DWU. In real life, Mao did not speak Hokkien, as he came from deep within rural Hunan Province, far away from the reach of Hokkien. This error is due to the Chinese actors coming from China's diaspora and not speaking standard Mandarin. (DWM 451)