One last comment about the Greeks. There were a variety of Greek cosmologies - precisely because there was no ultimate, absolute godhead envisioned from which all Truth emanated in an arbitrary fashion - that might best be summarized as follows: the Truth was the essence of the universe. There were two basic solutions to the search for Truth: (1) revelation; (2) reason.
Pythagoreanism is emblematic of the first: at its most basic, reality is the harmonics of the universe and you can reveal it by attuning yourself to the universe (a very 'Buddhistic' sensibility). There were variations depending on how one could achieve such a state and to what degree the Truth could be revealed, but they involved the same basic mindscape.
Of the second, there were two exemplars, one represented by Platonism and the other by Aristotelian thought, but one identical conclusion: The Truth was the essence of the universe. The difference between them was that the former perceived of this as independent Forms while the latter perceived of this as inherent forms. Now, it's worth noting that Plato was a rather bit eccentric by his own contemporary standards, but the basic conceptual division serves here.
In Plato's view, the universe was an illusion, and the Forms were eternal universals. The Forms were basically the archetypes of all that is, and could only be understood by pure reason. The gods were gods because they had no impediment between them and these ideals. They were not gods because they were the standard of Truth; rather, they were gods because they had a perfect knowledge of the Truth - i.e., the true essence of reality.
By contrast, Aristotle held that entities were self-contained forms - that an entity held within itself all the forms that it would express throughout the totality of its existence. So, although he agreed with Plato that the Truth was the essence of the universe, he disagree with Plato's notion that the essence of the universe was separate from the expression of the universe.
And all the Greeks basically fit to some degree or other within the boundaries outlined above: the Truth is the nature of the universe.
As a side note, Asimov once wrote -- in one of his rare moments of saying anything favorable about theism -- that the development of Western science might be, at least partially, attributable to our tradition of monotheism. That is, among the Greeks, the observation of confusing or inconsistent facts could be shrugged off as due to conflicts among the gods. In the monotheistic worldview, however, there had to be only one answer, one cause, one explanation.