I start by making two assumptions, as being facts known to every serious student of antiquity. One is, that Aeschylus was not only a poet but a theologian. The other is, that practically every Greek of that time, if he thought at all concerning deity, did so along mythological lines. The second postulate perhaps needs a little exposition. We have long got rid of the error which supposed the myths, or any of them, to form a kind of “pagan creed,” belief in which did or might constitute a test of orthodoxy. We know that creeds are rather rare phenomena, confined to a few religions, of which that of classical Greece was not one. No one in all Hellas was expected to declare that he believed in the Labors of Herakles, and no heresy hunts were started if someone doubted that Prometheus stole fire from heaven. Decent regard for the official cults was, indeed, in a general way, required of everyone, and the public conscience was liable to be shocked if some too bold thinker proclaimed that he did not accept the tacit assumption on which all such cults must rest, if their followers reflect on them at all, namely that certain beings superior to man exist. But everyone had from early childhood heard traditional tales about those beings, which agreed pretty well in their main outlines, no matter whether the teller or the hearer was Athenian or Boiotian, Spartan or Argive.