A summary sketch of so manifold a theme as that with which this short handbook deals will be of more value if it can present the facts in some kind of chronologic sequence. We may conveniently distinguish four periods: the first, the prehistoric, falling mainly in the second millennium B.C. and closing with the epoch marked by the Homeric poems; the second, extending from 900 to 500 B.C., beginning with the colonial expansion of Hellas and ending before the Persian invasion; the third, from 500 to 338 B.C., including the greatest century of Greek history and closing with the battle of Chæronea and the establishment of Macedonian supremacy; the fourth and last, the Hellenistic and Græco-Roman period. The chronologic statement is embarrassed by the absence of any record of date for the institution and diffusion of most of the cults and for the growth of certain religious ideas; nor can we safely date a religious fact by the date of the author who first mentions it; a detail of ritual, a myth, a religious concept, only attested by Pausanias or a late scholiast, may descend from an age centuries before the Homeric. And our earliest inscriptions do not {17} as yet reach back to a period earlier than the beginning of the seventh century. For determining our view of Greek religion in the second millennium B.C., when Hellenism was in the making, the poems of Homer and Hesiod are of priceless value if they are used with cautious and trained criticism. We depend greatly also on the general inductions of comparative religion and anthropology, which may sometimes guide us rightly in this matter, especially if the anthropological comparison is drawn from more or less adjacent communities rather than from the Antipodes. We depend also on the evidence of the monuments of the Minoan-Mycenæan religion, revealing glimpses of the practices and faith of a people of high culture, whom no one would dare now to call, at least in the earlier stage of their life, Hellenic, but from whom the earliest Hellenes doubtless adopted much into their own religion.