Heraclitus of Ephesus (c. 535-c. 475 BCE)
Biography (Internet Encyclopedia of Philosophy)
Biography (Stanford Encyclopedia of Philosophy)
Empedocles of Acragas (c.490-c. 430 BCE)
Biography (Internet Encyclopedia of Philosophy)
Biography (Stanford Encyclopedia of Philosophy)
Democritus of Abdera (c. 460-c. 370 BCE)
Biography (Stanford Encyclopedia of Philosophy)
Biography (Internet Encyclopedia of Philosophy)
Picture Credits
Thales: https://commons.wikimedia.org/wiki/File:Thales_1825_at_Alex._Onasis_Foundation.jpg
Heraclitus: http://tr1besman.blogspot.com/2012/03/heraclitus-of-ephesus-impermanence.html
Empedocles: By D. Cunego, 1785, after Raphael. Public Domain. Wikimedia Commons
Democritus: https://commons.wikimedia.org/wiki/File:Democritus2.jpg
Pythagoras Of Samos (c. 570- c. 495 BCE)
Biography (Internet Encyclopedia of Philosophy)
Biography (Stanford Encyclopedia of Philosophy)
Parmenides of Elea (Born c. 515 BCE)
Biography (Internet Encyclopedia of Philosophy)
Biography (Stanford Encyclopedia of Philosophy)
Picture Credits
Pythagoras: Public domain. Source
Parmenides: http://www.philosophybasics.com/philosophers_parmenides.html
Protagoras: https://commons.wikimedia.org/wiki/File:Euripides_Pio-Clementino_Inv302.jpg
Diogenes: Detail from the School of Athens by Raphael. Public domain. Wikimedia Commons