17 pages
The first beings
Before the Titans and the Olympians there were the primordial powers: Chaos, Earth, Night and what they bore.

In Hesiod's Theogony, the first thing to exist is Chaos, a gap or opening. After it come Gaia (Earth), Tartarus (the deep pit) and Eros (desire). Chaos alone produces Erebus (darkness) and Nyx (night). Night and Darkness then have two children, Aether, the bright upper air, and Hemera, Day.
Gaia, without a partner, bears Uranus (the sky), the Ourea (the mountains) and Pontus (the sea). She then takes Uranus as her partner, and their children are the Titans. The family tree on this site starts from this account.
A second tradition, in the poems attributed to Orpheus, begins differently, with Phanes emerging from a world-egg, or with Chronos (Time) and Ananke (Necessity). Late writers add figures such as Aion (eternity) and Achlys (mist). They are listed separately, with their sources, because they are not in Hesiod.
In Hesiod: from Chaos and Earth
In other traditions
Orphic, Hellenistic and later figures, with thinner evidence.