It is of course quite possible that the common gods grew out of the personification of natural phenomena, the solar-myth theory, on which nineteenth-century scholars sharpened their ingenuity.[21] It may be, too, that one or more of them are the national gods of the conquering Hellenes, whensoever and howsoever such a conquest may have taken place. Some may have been of relatively late importation. The Greeks lived in territory open to streams of influence from every point of the compass. Of one such importation we know some details—the worship of Dionysus.[22] Of others, such as Aphrodite, we suspect a Semitic origin by way of Cyprus.[23] It will be noticed that the names of most of the common gods are difficult to trace to Greek roots, a fact in itself of some significance. We must remember that the wandering of the god is often merely the wandering of a name. That is especially true in those cases in which an old divine name becomes the epithet or cult-title of the intruding deity. Here obviously there was no change in the nature of the god worshiped and no interruption of his worship. It is very likely, too, that very few deities ever completely disappeared, even when there was a real migration of a god. The new god took his place by the side of the old one, and relations of many kinds, superior or inferior, were speedily devised. So at Athens, in the contest between Poseidon and Athena, permanently recorded on the west pediment of the Parthenon, the triumph of Athena merely gave her a privilege. The defeated Poseidon remained in uninterrupted possession of shrine and votaries. How did the worship of certain gods spread? One answer is obvious: by the migration of their votaries. Locally limited as the operation of the divinity was, in normal circumstances there never was a doubt that it could transcend those limits when the circumstances ceased to be normal. And that certainly took place when the community of which the god was a member changed its residence. The methods of propitiation, as crystallized into the inherited ritual, and the divine name, in which, for the rank and file, the individuality of the god existed, would be continued, though they were subject to new influences, and not infrequently suffered a sea-change.