Zeus was born by the titans Cronus and Rhea. Titan Cronus was notorious for being a very jealous and greedy deity, swallowing every child Rhea was giving birth to, out of the fear one of his children could take his throne.
However, when Zeus was born, Rhea managed to trick Cronus with the help of the titans Uranus and Gaea, giving her husband a rock in swaddling clothes to swallow as a substitution to her infant. Rhea then sent Zeus away to the greek island of Crete.
Zeus was raised secretly by the Nymphs and was fed by the milk of the goat Amaltheia until he was mature enough to fulfill his role. He then started a battle against his father and the Titans, also known as "Titanomachy".
First Zeus liberated his five elder brothers and sisters from his father's stomach by giving him a special herb and making him this way throw up. Together with his siblings, Zeus then overthrew the titans in the depths of the Underworld, the Tartarus.
After overthrowing his father Cronus, Zeus was confronted with the Giants and the monster Typhoon, who he both battled successfully. Zeus then drew lots with his brothers Poseidon and Hades to justly determine who would become the new king of the gods. Zeus won the draw and officially became ruler of the Earth and the Sky and the Lord of Mount Olympus.