The same writer adds: "With the birch trees waving around, and these old symbols of once great religions before me, I felt thrilled by an impression of having reached a spot where the prehistoric religion could be traced visibly blending with Christianity." Tree and Serpent worship is the theme of many an ancient Greek myth. The destruction of the dragon Python by Apollo, who takes possession of the oracle which the serpent guarded; the conversion of Cadmus and his wife into serpents when they were regarded as objects of veneration; the story of the Argonautic expedition, which was undertaken to recover a fleece that hung on a tree guarded by a dragon; the strangling of serpents by Hercules; his adventure in the garden of the Hesperides, which reminds us of the garden of Eden, though with a different moral; his fight with Lernæan hydra; on the other hand, his intercourse with the serpent Echidna, through whom he is said to have become the progenitor of the whole race of serpent-worshipping Scythians; the keeping of serpents at Delphi and other places for oracular purposes; the serpent worship at Epidaurus, where stood the temple of Æsculapius and the grove attached to it; the contention between Athene and Poseidon for the guardianship of the city of Athens when the goddess created the olive, planting it on the Acropolis, and handed over the care of it to the serpent-god Ericthonius; the statement that when the Persians were approaching Athens the Athenians, though warned by the oracle, refused to leave their homes till they learned that the great serpent, the guardian of the city, had refused its food and left its place; the curious record concerning the descent of Alexander the Great from a serpent; the part which snakes played in the Bacchic cultus--all these tales show the tenacity of that early form of worship. Fergusson adds to this summary of his words by an American writer:--"The traces of Tree Worship in Greece are even fuller and more defined than those of the Serpent Cultus just alluded to. As each succeeding Buddha in the Indian mythology had a separate and different Bo-tree assigned to him, so each god of the classical Pantheon seems to have had some tree appropriated as his emblem or representative. Among the most familiar are the oak or beech of Jupiter, the laurel of Apollo, the vine of Bacchus. The olive is the well-known tree of Minerva. The myrtle was sacred to Aphrodite. The apple or orange of the Hesperides belonged to Juno. The populus was the tree of Hercules, and the plane-tree was the "numen of Atridæ."