Anaxagoras (Greek: Ἀναξαγόρας, Anaxagoras, "lord of the assembly"; c. 500 BC – 428 BC) was a Pre-Socratic Greek philosopher.
Born in Clazomenae in Asia Minor, Anaxagoras was the first philosopher to bring philosophy from Ionia to Athens. He attempted to give a scientific account of eclipses, meteors, rainbows, and the sun, which he described as a fiery mass larger than the Peloponnese. He was accused of contravening the established religion and was forced to flee to Lampsacus.
Anaxagoras is famous for introducing the cosmological concept of Nous (mind), as an ordering force. He regarded material substance as an infinite multitude of imperishable primary elements, referring all generation and disappearance to mixture and separation respectively.