Pythagoras

Pythagoras was an Ancient Greek philosopher and mathematician. (PROSE: Empire of Death)

Biography

The Doctor met him before their fourth incarnation. (AUDIO: The Labyrinth of Buda Castle)

The Fourth Doctor recalled Pythagoras as a lovely fellow who was good at billiards. (COMIC: Gaze of the Medusa)

The Thirteenth Doctor claimed to have borrowed some sunglasses from either Pythagoras or Audrey Hepburn. Graham pointed out that Pythagoras never was seen wearing sunglasses (since modern sunglasses weren't invented until the early 20th century), but the Doctor countered by implying he wore shades in a hangover. (TV: The Ghost Monument)

According to the Eighth Doctor, when a student of Pythagoras suggested to him that the square root of two is not a rational number, Pythagoras ordered to drown him. (PROSE: Option Lock)

Pythagoras was burned to death in his school. (PROSE: Option Lock)

Philosophical beliefs

Pythagoras believed in metempsychosis, i.e., transmigration of the soul, also known as reincarnation. (PROSE: Empire of Death)

Scientific achievements

Pythagoras was the first to discover that maths is the basis of science. (PROSE: Option Lock)

Pythagoras proved that the Earth revolved around the the sun 19 centuries before Copernicus. (COMIC: Gaze of the Medusa)

By plucking a string, he discovered that the relation of a note to its overtones is always a fraction. (PROSE: The Algebra of Ice)

Pythagoras proved a theorem that determined properties of a hypotenuse. (PROSE: Byzantium!)