A child of Cronus and Rhea, Zeus is the third ruler of the universe. The Gods were originally swallowed by their father, who feared that he would meet the same fate as his father Uranus. Only the youngest child, Zeus, was spared this fate. Under the advice of Gaia, when Zeus was about to be born, Rhea fled down to the Earth and hid Zeus in a Cretan cave. Taking a stone from the Earth, she returned and handed it to her husband Cronus. Without looking, Cronus swallowed the rock, presuming it to be his son.
On Crete, Zeus was raised by the divine goat Amaltheia. When Zeus was old enough, he left Crete and through strength and guile forced Cronus to vomit up the five other Gods, as well as the stone he thought to be his son. Falling to the Earth, the stone came to rest at Delphi, where the Oracle of Apollo was located. Zeus' own most prominent oracle was at Dodona, where his priests would interpret the wind as it whistled the the leaves of the oak trees.
With his brothers freed, Zeus and the Gods battled the Titans in the Titanomachy. Thanks to the help of their uncles the Cyclopes and Hecatoncheires, whom Zeus gave them nectar and ambrosia to restore their strength and then freed from their imprisonment in Hyperion to the west, the Gods eventually prevailed.
After the Titanomachy, the Titans were imprisoned in Tartarus, guarded there by the Hecatoncheires. Zeus, who had free his siblings and led them during the war, became the new king of the world. With his two brothers he divided the dominions of the world. Zeus' realm was the sky. From Olympus, Zeus reigns with his thunderbolts, the gifts of the Cyclopes. For this reason Hesiod often calls him the 'storm gatherer'.
Shortly after defeating the Titans, Zeus was given an even greater challenge from Typhaon, the last, and perhaps most powerful, son of Gaia. This fearsome creature had one hundred snake heads, each of which breathed fire and shrieked an indescribable sound. Only with supreme effort, Zeus eventually overcame Typhaon and banished him to Tartarus.
Aside from his role as the god of the sky, Hesiod also associates Zeus as a god of justice, with Dike (justice) beside him, and also the god of hospitality.
Zeus had many, many children. With his first wife, Metis, he fathered Athena. With his second wife, the Titan Themis, he fathered the Fates and Dike, among others. With the Oceanid Eurynome he fathered the Graces. In union with Demeter, Persephone was born. With the Titan Mnemonsyne he fathered the Muses. With Leto he had Apollo and Artemis. With his third and final wife Hera he had Hebe, Hephaestus and Ares. With Atlas' daughter Maia, he fathered Hermes. With the nymph Aegina, he fathered Aeacus.
Zeus did not overlook mortal women, either. Semele bore Dionysus with him. The great Heracles was born from Zeus' affair with Alcmene. According to Homer Zeus had three sons with Europa: Minos, Rhadamanthys and Sarpedon. He rained a golden shower upon the imprisoned Danae, and she gave birth to Perseus.
The Romans associated Zeus with Jupiter, a god of the sky. Fittingly, the first temple built (by Romulus) in Rome was dedicated to Jupiter. Jupiter also struck down the third king of Rome, Tullus Hostilius with a thunderbolt. This was because he had performed sacred rites for the god incorrectly.
Livy. Ab Urbe Condita.