In Greek mythology, Chaos (Greek: Χάος), the primeval void, was the first thing which existed. According to Hesiod, "at first Chaos came to be" (or was) "but next" (possibly out of Chaos) came Gaia, Tartarus, and Eros. Unambiguously born "from Chaos" were Erebus (Darkness) and Nyx (Night).
The Greek word "chaos" (χάος), a neuter noun, means "yawning" or "gap", but what, if anything, was located on either side of this chasm is unclear. For Hesiod, Chaos, like Tartarus, though personified enough to have born children, was also a place, far away, underground and "gloomy", beyond which lived the Titans. And, like the earth, the ocean, and the upper air, It was also capable of being affected by Zeus' thunderbolts.
- Hesiod, Theogony 116–122.
- Gantz, p. 3, says "the Greek will allow both".
- Tripp, p. 159; Morford, p. 57.
- Gantz, p. 4; Hesiod, Theogony 123.
- Gantz, p. 3.
- Hesiod, Theogony 814: "And beyond, away from all the gods, live the Titans, beyond gloomy Chaos".
- Hesiod, Theogony 700.
- Ovid, Metamorphoses 1.5 ff..
- Hyginus, Fabulae Preface. According to Bremmer, p. 5, "Hyginus ... started his Fabulae with a strange hodgepodge of Greek and Roman cosmogonies and early genealogies. It begins as follows: Ex Caligine Chaos. Ex Chao et Caligine Nox Dies Erebus Aether (Praefatio 1). His genealogy looks like a derivation from Hesiod, but it starts with the un-Hesiodic and un-Roman Caligo, ‘Darkness’. Darkness probably did occur in a cosmogonic poem of Alcman, but it seems only fair to say that it was not prominent in Greek cosmogonies."
- Ogden, pp. 36–37.
- Bremmer, Jan N. (2008). Greek Religion and Culture, the Bible and the Ancient Near East. Jerusalem Studies in Religion and Culture. Brill. ISBN 9789004164734. LCCN 2008005742.
- Gantz, Timothy, Early Greek Myth: A Guide to Literary and Artistic Sources, Johns Hopkins University Press, 1996, Two volumes: ISBN 978-0-8018-5360-9 (Vol. 1), ISBN 978-0-8018-5362-3 (Vol. 2).
- Hesiod, Theogony, in The Homeric Hymns and Homerica with an English Translation by Hugh G. Evelyn-White, Cambridge, MA.,Harvard University Press; London, William Heinemann Ltd. 1914.
- Morford, Mark P. O., Robert J. Lenardon, Classical Mythology, Eighth Edition, Oxford University Press, 2007. ISBN 978-0-19-530805-1.
- Ogden, Daniel, Dragons, Serpents, and Slayers in the Classical and early Christian Worlds: A sourcebook, Oxford University Press. ISBN 978-0-19-992509-4.
- Ovid, Metamorphoses, Brookes More. Boston. Cornhill Publishing Co. 1922. Online version at the Perseus Digital Library.
- Smith, William; Dictionary of Greek and Roman Biography and Mythology, London (1873). "Chaos"
- Tripp, Edward, Crowell's Handbook of Classical Mythology, Ty Crowell Co; First edition (June 1970). ISBN 069022608X