Plato

Plato was an ancient Greek writer and philosopher and was the student of another known philosopher, Socrates.

The Doctor's companion, Vicki, had never heard of either Plato or Socrates. (PROSE: Byzantium!)

The Fourth Doctor and Leela met Plato at a gathering at Anaximander's home. (PROSE: The Brain of Socrates)

The Library of St John the Beheaded contained some of his lost works. (PROSE: All-Consuming Fire)

Bernice Summerfield met Plato and his Socrates whilst time-travelling. (AUDIO: The Oracle of Delphi)

The Eleventh Doctor, Amy Pond and Rory Williams also met him and his mentor. (COMIC: The Chains of Olympus)