In Greek myth and religion, Zeus is
the supreme god, the youngest ( according to Homer the eldest) son
of Chronus whom he overthrew and succeeded. His name indicates an
Indo-European origin, being found in the Indic sky-god Dyaus pita,
the Roman Jupiter, the Germanic Tues-day, Latin deus,
'god', dies 'day', and Greek eudia, 'fine weather'.
For the Greeks he is the god of weather rather than of the 'bright
sky' of day. According to his Homeric epithets he is the
cloud-gatherer, the thunderer on high, hurler of thunderbolts. He
was born in Crete, according to what is probably the oldest myth,
or was born in Arcadia and brought to Crete, where he was hidden
in a cave on Mount Dicte or Mount Ida and fed by the goat
Amalthea. The Curetes, in order to conceal him, drowned his cries
by their noisy ritual. (The Cretans also had a peculiar myth of
Zeus dead and buried.) After the overthrow of Cronus, Zeus and his
brothers divided the universe by casting lots, Zeus obtaining the
heavens, Poseidon thc sea, and Hades the underworld. Zeus dwells
on the tops of mountains where the storm clouds gather, on Mount
Lycaeus in Arcadia, or Mount Ida near Troy, or on Mount Olympus,
the highest mountain in northern Thessaly. The thunder-bolt, which
only he commands, signifies his irresistible power, over other
gods as well as men, and it enabled him to defeat the Titans the
Giants, and Typhoeus. Thus it is Zeus who must be supplicated to
grant victory in war. He is the protector of political freedom,
Zeus Eleutherios ('liberator'), or Soter ('sav-iour'), and
festivals were instituted in his honour. After the Greek victory
at Plataea in 479 BC, a sanctuary for Zeus Eleutherios and the
festival of the *Eleutheria were instituted.
Zeus is the only Greek god to have as children other powerful gods, Apollo, Artemis, Hermes, Dionysus, Athena, and Persephone. By his wife Hera he was the father only of Ares, Hebe and Eileithyia. The mother of Athena, Metis (Wisdom), was fated to have a second child more powerful than its father, and so Zeus swallowed her, thereafter combining supreme power and wisdom within himself His mortal children included Heracles, Helen, Perseus, Epaphos, Minos, and the brothers Amphion and Zethus. Zeus is called the father of gods and men and had perhaps been so addressed since Indo-European times, although he is not the father of all the gods and did not create men (for stories about the creation of men see DEUCALION and PROMETHEUS). Epithets added to his name indicate his particular roles: he is father in the sense of ruler and protector, defender of the house (Herkeios), of the hearths (Ephestios), of the rights of hospitality (Xenios and Hikesios), of oaths (Horkios), and the guardian of property (Ktesios), his image set up in the store room. He is also the protector of law and morals; in that capacity the poet Hesiod evokes him in Works and Days, and represents the goddess of justice, Dike, as enthroned beside him. The impartiality of his judgements is represented by Homer in the lliad in the image of Zeus holding golden scales in his hand; as Achilles and Hector fight, the fall of a pan indicates that Hector is doomed. Zeus has the power, if he wishes, to save Hector whom he loves, as he might have saved his own son Sarpedon, but it is men's 'fate' (moira) or 'portion' (aisa) to die, and Zeus does not overrule the apportionment (see FATE).
Zeus is also called Chthonios, 'of the Earth'. Sometimes the phrase simply stands for Hades or Pluto, the god of the Underworld, the sky god is not meant. More oftcn the phrase signifies Zeus whose all-embracing power extends into the earth as well, from whom the growth of crops is expected. Apart, however, from general overseership given by his position of supremacy. Zeus had little to do with the day to day concerns of men, war, agriculture, crafts, etc.; but the wide scope of his functions made him unique in his importancc to all Greece. His festival at Olympia asserted his supreme position and the cssential unity of all who worshipped him. To participate in his festival was to be a Hellene; the admission of the Macedonians and later of the Romans were events of great political significance. His universality, of which the beginnings are apparent in Aeschylus, paved the way for the later philo-sophical pantheism of the Stoics. He corresponds to, and was identified with, the Roman Jupiter.
Taken directly from the Oxford Companion to Classical Literature