The Titans
Before the Olympian Gods, there were the Titans. The 12 Titans were born from Gaia(mother earth) and Uranus(sky) and they included the pairs: Cronus and Rhea, Iapetus and Themis, Oceanus and Tethys, Hyperion and Theia, Crius and Mnemosyne, and Coeus and Phoebe.
Uranus was the king of the Titans and he ruled the world. Upon learning from a prophecy that he will be overthrown by one of his children, he grew fearful and anxious. As a result, he shut all of his chidren inside his wife, Gaia the Earth. Gaia resented his husband for imprisoning their children so he helped Cronus overthrow Uranus using a sickle that rendered his powers useless.
Uranus was the king of the Titans and he ruled the world. Upon learning from a prophecy that he will be overthrown by one of his children, he grew fearful and anxious. As a result, he shut all of his chidren inside his wife, Gaia the Earth. Gaia resented his husband for imprisoning their children so he helped Cronus overthrow Uranus using a sickle that rendered his powers useless.
The Olympian Gods
After overthrowing his father, Cronus and Rhea had children of their own. These children included the Olympians Hestia, Hera, Demeter, Poseidon, Hades, and Zeus. Just like his father, Cronus was terrified of his own children. However, he wasn't going to make the same mistake that his father had done so instead of imprisoning the Olympians, he consumed them and stored them inside his own body. Rhea, the wife of the ruler, was once again unhappy about the husband's treatment of their children so she tricked Cronus into eating a piece of stone and making him think that it was Zeus. Secretly, Rhea raised Zeus until he was old enough to break into his own father and free his siblings. Finally, he became the leader of the Gods and claimed his throne on Mount Olympus.