What is the basic hierarchy of the Greek Gods?
Before there was Zeus and his brothers and sisters, his parents were Gaea and Uranus. They had the Titans, which were Zeus, Poseidon, Hades, Hera, Demeter and Hestia. Zeus and Hera ruled Olympia and divided the world into parts that the six of them could rule. Because Zeus was the one who saved them all from their father, he ruled all. These links should help with details.
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