Legends of Greece and Rome
Zeus
Zeus was supreme ruler of Olympus and the world. He controlled the elemental powers such as thunder, lightning and rain. He possessed the Aegis (believed to have been a shield or breastplate covered in Almaltheia's hide), which would produce a great thunder storm to protect Zeus from foes.
Zeus was a promiscuous god and produced many children as a result of his numerous affairs. His first consort was Metis (wisdom (the daughter of the Titans Oceaenus and Tethys)) who had looked after him as a child on the island of Crete.
When Metis became pregnant, Gaea and Uranus warned Zeus that the child may become greater than he was. He swallowed the child at birth and was immediately filled with wisdom. Some time later, the goddess Athena emerged full grown and fully armed, from his head.
Hera
Hera was the wife and sister of Zeus and the goddess of family, familial love and legitimate childbirth. She personified marital fidelity and became outraged by Zeus' extramarital affairs. There are many tales of the consequences of her anger at Zeus' consorts and illigimate children.
Io, the princess of Argos, was one of these consorts who Zeus transformed into a white cow to protect her from Hera's wrath. Hera was not fooled by this deception however and ordered the hundred eyed heardsman, Argus, to watch over the cow, as she believed that Zeus would eventually attempt to change his lover back into her original form. Zeus sent Hermes (the god of trickery) to distract Argus and, after much time, Hermes managed to lull Argus into a deep sleep and then killed him (he placed the hundred eyes into the tail of the peacock).
Before Zeus could transform Io again, Hera sent a gadfly to torment the cow. Io ran wildly in an attempt to escape the fly. She ran across great distances and swam oceans. Eventually she managed to escape the fly in Egypt. by this time hera believe Io dead and forgot about her. Zeus made love to Io again and she gave birth to Ephastus, a forefather of Heracles.
Source: 'Myths and Legends of Ancient Greece and Rome'
Morgan J. Roberts
