Philolaus  Philolaus (; , "Philólaos"; ) was a Greek Pythagorean and pre-Socratic philosopher. He argued that at the foundation of everything is the part played by the limiting and limitless, which combine together in a harmony. He is also credited with originating the theory that the Earth was not the center of the Universe. According to August Böckh (1819), who cites Nicomachus, Philolaus was the successor of Pythagoras. Philolaus is variously reported as being born in either Croton, or Tarentum, or Metapontum—all part of Magna Graecia (the name of the coastal areas of Southern Italy on the Tarentine Gulf that were extensively colonized by Greek settlers). It is most likely that he came from Croton. He may have fled the second burning of the Pythagorean meeting-place around 454 BC, after which he migrated to Greece. According to Plato's "Phaedo", he was the instructor of Simmias and Cebes at Thebes, around the time the "Phaedo" takes place, in 399 BC. This would make him a contemporary of Socrates, and agrees with the statement that Philolaus and Democritus were contemporaries. The various reports about his life are scattered among the writings of much later writers and are of dubious value in reconstructing his life. He apparently lived for some time at Heraclea, where he was the pupil of Aresas (maybe Oresas), or (as Plutarch calls him) Arcesus. Diogenes Laërtius is the only authority for the claim that Plato, shortly after the death of Socrates, traveled to Italy where he met with Philolaus and Eurytus. The pupils of Philolaus were said to have included Xenophilus, Phanto, Echecrates, Diocles, and Polymnastus. As to his death, Diogenes Laërtius reports a dubious story that Philolaus was put to death at Croton on account of being suspected of wanting to be the tyrant; a story which Laërtius even took the trouble to put into verse. Diogenes Laërtius speaks of Philolaus composing one book, but elsewhere he speaks of three books, as do Aulus Gellius and Iamblichus. It might have been one treatise divided into three books. Plato is said to have procured a copy of his book from which, it was later claimed, Plato composed much of his "Timaeus".