Epicurus - Greek philosopher; founded the system known as Epicureanism.He studied with followers of Plato and Democritus before opening his school in Athens.
Pythagoras - Greek philosopher and mathematician; held that numbers were basic to matter; the Pythagorean Theorem is named for his geometric formulation; developed atomic theory; students of his philosophy emphasized geometrical form as a basic property of atoms; developed mathematical relationships which led to musical harmony.
Copernicus discovered the mathematically yet unproven heliocentric solar system.
In his treatise, 'On the Revolutions of the Celestial Spheres' he postulated that the planets, including the earth, revolve around the sun, and that the earth revolved around its axis once every day.
He also played an importqant role in the development of the Western or Sicilian school of Greek medicine.
He cured a plague at the Sicilian city of Selinus and claimed he was a god.