Meanwhile philosophy began to flourish in more definite shape among the colonists of Asia Minor, Italy, and Sicily. The criticism of the Theogony of Hesiod led the Ionian thinkers--Thales, Anaximenes, Anaximander, Heraclitus--to evolve separate answers to the question of the origin of the universe. The problem of the physical #archê#, or starting-point, of the world occupied their attention. Some more scientific theory of existence than mythology afforded was imperatively demanded. The same spirit of criticism, the same demand for accuracy, gave birth to history. The Theogony of Hesiod and the Homeric version of the Trojan war, together with the genealogies of the heroes, were reduced to simple statements of fact, stripped of their artistic trappings, and rationalized after a rude and simple fashion by the annalists of Asia Minor. This zeal for greater rigor of thought was instrumental in developing a new vehicle of language. The time had come at length for separation from poetry, for the creation of a prose style which should correspond in accuracy to the logical necessity of exact thinking. Prose accordingly was elaborated with infinite difficulty by these first speculators from the elements of common speech. It was a great epoch in the history of European culture when men ceased to produce their thoughts in the fixed cadences of verse, and consigned them to the more elastic periods of prose. Heraclitus of Ephesus was the first who achieved a notable success in this new and difficult art. He for his pains received the title of #ho skoteinos#, the obscure--so strange and novel did the language of science seem to minds accustomed hitherto to nothing but metre. Yet even after his date philosophy of the deepest species was still conveyed in verse. The Eleatic metaphysicians Xenophanes and Parmenides--Xenophanes, who dared to criticise the anthropomorphism of the Greek Pantheon, and Parmenides, who gave utterance to the word of Greek ontology, #to on#, or being, which may be significantly contrasted with the Hebrew I am--wrote long poems in which they invoked the Muse, and dragged the hexameter along the pathway of their argument upon the entities, like a pompous sacrificial vestment. Empedocles of Agrigentum, to whom we owe the rough-and-ready theory of the four elements, cadenced his great work on Nature in the same sonorous verse, and interspersed his speculations on the cycles of the universe with passages of brilliant eloquence.