With the emergence of Greece in the seventh century from the dark ages that followed the Mycenaean civilization, we find that certain beliefs, expressed or only hinted at in the Homeric poems, come to the surface, and that religious ideas imported from without make themselves manifest. The cult of the dead for example is almost passed over in silence by the Homeric poems. At the funeral pyre of Patroclus Achilles offered jars of oil and honey, and slew horses, dogs, and twelve Trojan youths[71]; but nowhere else is such a sacrifice mentioned in the Iliad. Likewise in the Odyssey the only instance of any similar offering is in the description of Odysseus’ visit to the borders of the realm of Hades to consult the shade of the seer Teiresias, where it is said that he dug a square pit, poured into it a triple chrism, and then after prayer and vows let the blood of a ram and a black ewe flow into it to attract the shades.[72] Yet we know from archeological and other evidence that the worship of the dead was common in Greece from the Minoan and Mycenaean times throughout antiquity. Ceremonial purification also, of which there are but few instances in Homer—and none of these is magical—now appears common, as a notion of impurity attaches to many conditions and acts which require expiation. The change in sentiment with regard to murder will serve as an illustration. In the Homeric poems killing brought no pollution either to the murderer or to his land; but in the Cyclic epics, which date from the seventh and sixth centuries B.C., bloodguilt required expiation just as in the later tragedies. So in the Aethiopis Achilles went to Lesbos to be cleansed from the stain of having slain Thersites. In fostering and directing rites of purification the oracle of Apollo at Delphi played an important part. There was developing, indeed there had been developing from an unknown period, a sense of defilement and of the necessity of cleansing. At this point, however, I must again speak a word of caution. We need to remember that morality develops slowly. It is undoubtedly a far cry from the morality of the seventh century to Plato’s definition of the impure man as the one whose soul is base, or to that motto which in a later century was written over the entrance of the shrine of Aesculapius at Epidaurus, “Piety consisteth in holy thoughts.” We must bear in mind that to the man of the seventh and sixth century sin and purification were primarily if not wholly ceremonial matters, and that his concept of future happiness was largely material. But the consequence of his feeling was great in future centuries.