Zeus is the sky and thunder god in ancient Greek religion and mythology, who rules as king of the gods on Mount Olympus. His name is cognate with the first syllable of his Roman equivalent Jupiter.

As polytheistic systems evolve, there is a tendency for one deity to achieve preeminence as king of the gods. This tendency can parallel the growth of hierarchical systems of political power in which a monarch eventually comes to assume ultimate authority for human affairs. Other gods come to serve in a Divine Council or pantheon; such subsidiary courtier-deities are usually linked by family ties from the union of a single husband or wife, or else from an androgynous divinity who is responsible for the creation.