When groups of Indo-European raiders invaded Greece at the beginning of the second millennium bc, they did not arrive without religious baggage. On the contrary, it is surprising how much of later classical belief and practice goes back to this early heritage. Linguists have concluded that the early Indo-Europeans worshipped a divine family consisting of a Sky Father (*Dyeus pater), his wife the Earth Goddess (*Pltwi mater), a Daughter of the Sky (*Diwos dhugeter), and twin Sons of the Sky (*Diwos sûnû) – all figures in the Greek pantheon.Footnote ¹ The Sky Father became Zeus, still the most prominent god, but the name of his one-time wife only survived in a small town, Boeotian Plataea.Footnote ² In ancient India, the Daughter of the Sky was Dawn, Usas, whose name survived as Eos,Footnote ³ but she was no longer a ‘daughter of Zeus’; that title was now used for other goddesses, such as Athena, Artemis, and, especially, Aphrodite.Footnote ⁴ Finally, the twin Sons survived as the Dioskouroi, whose name reflects the fact that they had become role models for the military age-set of youths beyond adolescence in pre-Homeric times, the kouroi.Footnote ⁵ In some cases, then, we note continuity in structure not name, in others continuity in name not structure, but it is important to note that in all these cases continuity does not mean lack of change: tradition always has to be appropriated.

The raiders also had a vocabulary of the sacred, as both hagnos and hieros (Chapter I, §1) go back to Indo-European times. They prayed with hands raised and practised libation: spondê derives from an Indo-European root *spend, ‘to make a libation’, and choê is connected with Sanskrit hotra, ‘sacrifice’, and Iranian zaotar, ‘sacrificial priest’.Footnote ⁶ Burkert has suggested that they also practised animal sacrifice, arguing from the term ‘hecatomb’, that is, ‘an act which brings in 100 oxen’. However, the term originally meant ‘a sacrifice of 100 oxen’, as additional evidence has since shown, but the continuity between hunt and sacrifice (Chapter IV, §2) further supports Burkert's suggestion.Footnote ⁷

Finally, the invaders brought a poetic tradition, which transmitted not only myths about great heroes and the prime interests of their society (Chapter V, §2),Footnote ⁸ but probably also contained traditions about the gods, since their Homeric epithet dotêres eaôn, ‘givers of good things’, suggests poets singing of the gifts of the gods.Footnote ⁹ The same conclusion is suggested by the presence in Linear B texts of formulae such as ‘Mother of the Gods’ and ‘Drimios, the son of Zeus’, which presuppose a divine genealogy.Footnote ¹⁰

After their invasion on the mainland, the proto-Greeks merged with the existing population, of whose religious tradition there is not much to say given the absence of any early texts or pictorial representations. The Linear B texts which survived the fires that destroyed the Minoan and Mycenaean palaces in the fourteenth and thirteenth centuries already suggest a unified pantheon which had incorporated Indo-European and autochthonous gods: Zeus but also Athena and Hera. We see here the contours of later Greek religion appearing. But what about the influence of Minoan Crete or Santorini, where the discovery of wall frescoes has shown a high standard of culture? The patient work of archaeologists is making it increasingly clear that Minoan elements on the mainland were more a veneer than integrated parts of a religious system, but, contrary to long-received wisdom, there never was a Minoan–Mycenaean religion. The Cretan legacy to Greek religion was relatively small, though not negligible.Footnote ¹¹

Especially during the archaic age, but probably also earlier, Greece experienced considerable religious influence from Anatolia, of which the ancient languages have become increasingly well understood in the last three decades, and from the Orient (Chapter 1, §3). It is probable that the familiar picture of the Homeric assembly of the gods, but also the phenomenon of divine epithets, such as ‘cloud-gathering’ Zeus, derived from Oriental epic. On the ritual level, there seem to have been wandering Oriental healers and diviners, who imported into Greece ritual techniques that are clearly recognisable as Oriental,Footnote ¹² such as hepatoscopy (divination from livers of sacrificed animals), foundation deposits, rites of purification, and technologies of magic. Greek religion, then, was the composite product of many traditions.