Turning to Greece we have the testimony of Prof. Max Mueller to this effect: "When we ascend to the distant heights of Greek history the idea of God, as the Supreme Being, stands before us as a simple fact." (_"Essays,"_ II, p. 146.) Carl Boettcher, in his great work on the Treeworship of the Greeks, maintains: "As far as the legends of the Greeks can be traced into prehistoric ages, the entire nation worshipped a single God, nameless, without statues, without a temple, invisible and omnipresent." This he regards as a tradition of "irrefutable inner truthfulness.... The beginning of Polytheism therefore represents the _second_ phase of Greek religion, which was preceded by a Monotheism." Every student of Greek literature knows that this original belief at an early age gave place to a worship of the gods on Olympus, a worship which in turn gave way to openly avowed atheism. The Greeks were aware of this decay. Plato, in his Phaidros (274 B) quotes Socrates as saying: "I know of an old saying, that our ancestors knew what constituted the true worship of God; if we could but discover what it was, would we then have need of _human_ theories and opinions on the matter?" Certainly a startling statement from the lips of a pagan. Undoubtedly Welcker was right when he asserted, as the ultimate result of his researches: "This (Greek) polytheism has settled before the eyes of men like a high and continuous mountain range, beyond which it is the privilege only of general historical study to recognize, as from a higher point of view, the natural primitive monotheism." Concerning the monotheistic ideas of later Greek thought, the same author says that they are to be regarded not as a result of an ascending line of evolution ("aufsteigende Linie der Entwickelung"), but as "a _return_ of the profound wisdom of old age to the feeling of primitive simplicity." Of the Phoenicians the greatest student of their history and religion, F. K. Movers, says: "Nature worship gradually obscured the purer God-idea of a more ancient stage of belief, but has never entirely obliterated it." He refers to an evident "adulteration of a purer and more ancient God-idea." Regarding the Zoroastrians of ancient Persia, M. Haug, the famous Zend scholar, asserts that "Monotheism was the leading idea of Zoroaster's theology;" he called God Ahura-mazda, i. e., "the Living Creator." Zoroaster did not teach a theological Dualism. He arrived "at the idea of the unity and indivisibility of the Supreme Being," and only as "in course of time this doctrine was changed and _corrupted_ ... the dualism of God and the devil arose." "Monotheism was _superseded_ by Dualism."