Chaos, the primeval state of existence
According to Hesiod's poem, the "Theogony" (written around 700 BC), which can be considered as a reflection of popular beliefs, in the beginning there was Chaos as a primeval state of existence. Chaos was the primal emptiness- a dark, silent, formless and infinite oddity with no trace of life.
Out of Chaos, Mother Earth Gaea first came to existence. Full of life and power, Gaea created high mountains, low lands, rivers, lakes and seas.
Soon, Chaos created Tartarus, the embodiment of the Underworld who built his home deep below the World of Gaea.
Gaea and Tartarus united and created Typhoeus (Typhoon), an appalling, fire breathing dragon with hundred heads.
Then, love appeared out of Chaos, in the form of Eros. Eros was the most handsome of all Greek gods, representing the love that softens hearts, invincible by nature.
Chaos also gave birth to Erebus, the symbolization of the dark silence, and Nyx, the embodiment of the night. With the intervention of Eros, Erebus and Nyx united and Nyx created Aether (the Atmosphere) and Hemera (the Day).
Greek Mythology - Family Tree of the First Greek Gods