Born in Ephesus (6th century BC) (today's Turkey), Heraclitus is also called the "Weeping Philosopher" because he used to sit in Ephesos and cry over mans feebleness and foolishness.
Heraclitus believed that the world was in a constant state of change, and his statement Ta Panta Rei ("Everything Floats") is his best known quote.
He also illustrated his belief in everythings fluxuality by saying you cannot step in the same river twice. He meant that change was the only true reality.
Heraclitus also said that fire was the primordial source of matter, and he occupied himself with ethics and theology, and is also considered to ave founded the Greek metaphysics. He attacked the popular religion and its concepts and ceremonies.
The philosopher ended his days as a hermit, trying to live of the grass on the ground. When this failed he tried to cure himself by sitting on a pile of warm manure, where he died.