ZEUS (Ζεός). — From a root Δυμός (cf. Sanskrit Dyauh), “to shine, to gleam,” he is the great god of the Aryan peoples from India to Europe, the personification of the sky under its twofold astronomical and meteorological aspect.
The universality of his conception is explained by the fact that atmospheric and celestial phenomena cannot be localized. All the epithets concerning him relate to his fundamental uranian character. He is the Most High (ὕψιστος), the Gatherer of Clouds (μελανικρῆς), the hurler of the thunderbolt while shaking the aegis (αἰγίοχος), the giver of rain (ὑέτιος) but also of clear weather (ὁρίβος, αἰθέριος). The mountains from which the broadest horizon of sky can be seen are sacred to him: typical is snow-covered Olympus, whose summit is always encircled by clouds.
As the deity of all the Greek tribes, he was an extremely effective instrument of their fusion, fostering a divine conception superior to that of the local divinities, which he subsequently assimilated by assigning their characteristics to himself as epithets. Thus it may be said of him that he is the most Hellenic of all the gods, since all the Hellenic tribes recognized themselves in him. For this reason he is found at the center of the moral life of the Greeks as an element of civilization, and at the center of their political and social life as an element of union.
As guardian of moral life, he is the protector of the city (πολιεός), presides over assemblies (ἀγοραῖος), safeguards the boundaries of property (ἔρχειος), protects the stranger (ἔξχειος), assists suppliants (ἰκέριος), carries out the will of the Moirai (Fates), that is, of fate, which is a destiny of death (μοιραγέτης), but cannot alter it (a limitation that is a tribute to the idea of God, since it acknowledges the dominion of a norm that counterbalances the caprice of the gods); he unites spouses (γαμήλιος), protects the bonds of kinship (συγγένιος), is patron of purifications (καθάριστος) and expiations (μελλίγιος), and avenger of oaths (ὄρκιος); he is the Greek deity par excellence (ἐλληνιος πανελλήνιος).
As guardian of social and political life, Z., as the fusion of regions and tribes gradually takes place, begins to absorb the various local cults. Thus in Crete he is Z. Κρεταγενής, absorbing the characteristics of a local vegetation deity who annually dies and is reborn; in Arcadia he is Z. Λυκαῖος, certainly replacing a very ancient animal cult involving human sacrifice; at Dodona, Z. Δωδωνίος, a local god who reveals the future through the rustling of the leaves of the oak that represents him; Z. τροφώνιος at Lebadea, in the cave of the same name, where he replaces an oracular demon; Z. Ὀλυμπέος at Olympia in Elis, around whose temple the games were celebrated that became the strongest cement binding the Hellenic tribes, and from whose four-year succession in time the years were reckoned (Olympiads).
From Homer, where many of these aspects are already present, Z. appearing as the god of lightning and lord of meteorological phenomena (Iliad, X, 5, 7; XII, 252; XVII, 548-50), inhabitant of the mountains (ibid., VIII, 47-52; XV, 151-53; XXIV, 308), father of gods and men (ibid., XVI, 225 ff.), avenger of oaths (ibid., V, 155), executor of fate (ibid., XXI, 82), down to Aeschylus, literature increasingly affirmed and ennobled the concept of Z., so much so that Aeschylus (frg. 345) says of him: “Z. is the aether, Z. is the earth, Z. is the sky, Z. is everything, and that which is above the whole” (v. αἰονή).