Metempsychosis.

Pythagoras is associated with the theory of metempsychosis in which the soul of the dead is reborn into another body.

Pythagoras, born on the Aegean island of Samos in the 6th century B.C. and active in southern Italy, was an ancient Greek philosopher and mathematician best known for a theorem in geometry that was named for him.
Pythagoras is credited with founding a philosophical school that deviated from the male-dominated Greek norms by allowing women to participate equally. The teachings of the school aren't strictly what we think of as philosophical. They also include rules on living and what to eat.