Who ruled before Zeus?

Answer 1

According to greek mythology, at the beginning of the world there existed beings called Protogenoi, meaning 'first-born'. They were the representations of phenomena such as the void (Chaos), the earth (Gaia) and fate (Ananke). They were incorporeal, immortal, and made up the fabric of the universe.

These Protogenoi gave rise to other deities and spiritual creatures, such as nymphs, and, most powerfully, the Titans - the children of Uranus (the sky) and Gaia.

The leader of these was Cronus, the first-born Titan. His offspring were the original Olympian Gods.

Answer 2

Zeus's father Cronus ruled with his wife Rhea when Rhea gave birth to Zeus.