Buddhism
Buddhism was an Earth religion whose adherents followed the teachings of Buddha.
Among the prizes that the First Doctor obtained during a game of backgammon against Kublai Khan in the 1289 was the sacred tooth of Buddha which Marco Polo had brought from India. At the Khan's court, Polo had previously seen Buddhist monks make cups of wine fly to the Khan's lips. (TV: Marco Polo)
The monks at the Det-Sen Monastery in Tibet were Buddhist. (TV: The Abominable Snowmen)
K'anpo Rimpoche became the abbot of a Buddhist meditation centre in England. (TV: Planet of the Spiders)
As a result of his experiences in UNIT, Brigadier Lethbridge-Stewart adopted Zen Buddhist practices. These helped him resist Vardan mind control as well as giving him a new perspective upon the Doctor and his role in the cosmic order (that is, as a Bodhisattva of Justice and Compassion). (PROSE: No Future, PROSE: The Shadows of Avalon)
