Anaxagoras (an-ax-ag'-o-ras), a Greek philosopher of the Ionian school, born at Clazomenae, 500 B.C. He studied under Anaximenes and, after traveling through all the known parts of the globe in search of knowledge, established himself at Athens, where he opened the first school of philosophy. He introduced the dualistic explanation of the universe, distinguishing sharply between mind and matter. Pericles, Socrates, and Euripides were among his pupils. He was condemned to die for alleged impiety, a sentence which was changed to exile, whereupon he retired to Lampsacus, and there continued to teach philosophy until his death, 428 B.C.