Gaia does not fight. She plans. Every overthrow in the Greek succession myth is her idea, and she switches sides each time.
It is her sickle that unmans Ouranos, and her suggestion, made to children who are afraid to act — only Cronus agrees, and she arms him and hides him in ambush. When Cronus turns out to be as bad as his father and swallows his children, it is Gaia and Ouranos who warn Rhea and receive the pregnant mother in Crete, and Gaia who takes the infant Zeus to hide. Once Zeus is in power and has imprisoned her Titan sons, she turns on him too: she brings forth the Giants and, finally, Typhon, the last and most dangerous opponent the Olympian order faces.
Three regimes, three conspiracies. She is not a serene mother-earth; she is the permanent opposition.
The oldest oracle
Aeschylus opens the Eumenides with the Pythia listing the succession of owners of Delphi: first Gaia, then Themis, then Phoebe, and then Apollo, who receives it as a birthday gift without violence. That is a peaceful, orderly transfer — and it is a deliberate revision. The Homeric Hymn to Apollo has him take the site by killing the great she-serpent that guarded the spring, and Euripides' Iphigenia among the Taurians has Earth resist the takeover by sending prophetic dreams to humans until Apollo complains to Zeus and has them stopped.
Whether Delphi was an earth oracle before it was Apollo's is one of the long-running questions in the study of Greek religion. The literary tradition says yes and is consistent across several authors; the archaeology has not produced a clear pre-Apolline oracular cult on the site. What is certain is that Greeks themselves believed prophecy came up out of the ground and belonged to her first — Pausanias reports an oracle of Gaia at Olympia and another at Aigai, and oracular incubation, in which the enquirer sleeps on the earth, belongs to that idea.
Sworn by, and rarely built for
She has few temples and appears constantly in oaths. Agamemnon's truce-oath in the Iliad calls on Zeus, Helios, the rivers, and Earth; treaties routinely invoke her; and the reason is straightforward — she is under everyone, she receives the dead, and she cannot be evaded. Her epithets in Attic cult include Kourotrophos, nurse of the young, and she receives offerings at sowing and harvest and at the boundaries between the living and the dead. The Athenians sacrificed to Ge Olympia near the Olympieion, and the Semnai and other chthonic powers overlap with her.
The Homeric Hymn to her is a farmer's prayer: eldest of beings, who feeds everything on the land, whose favour makes the fields heavy with grain and the flocks numerous and the house full of good things, and whose children rejoice in the flowering meadows.
The children who are not gods
Her offspring by Ouranos are the twelve Titans, the three Cyclopes and the three Hundred-Handers. By Tartarus she bears Typhon. By Pontus, the sea, she produces Nereus, Thaumas, Phorcys, Ceto and Eurybia, and through Phorcys and Ceto the whole line of monsters — the Gorgons, the Graiai, Echidna. From the blood of the castrated Ouranos falling on her come the Erinyes, the Giants and the Meliae, ash-nymphs.
Some of her children are simply produced without a partner at all, which is the point being made: the earth generates. She is also given a role in specific local births — Erichthonius of Athens, conceived when Hephaestus' seed falls to the ground, is literally hers, which is what makes the Athenians' claim to be autochthonous, sprung from their own soil, a genealogical statement rather than a metaphor. Antaeus, who could not be beaten while touching the ground, is her son, which is why Heracles lifts him.
Terra, Tellus and the earth as a state
The Roman Terra Mater and Tellus had real cult: the Fordicidia in April, at which pregnant cows were sacrificed and the unborn calves burned by the Vestals, and a temple vowed in 268 BCE. The most famous image is the panel of the Ara Pacis in Rome, where a serene female figure with two infants sits among animals and grain — usually identified as Tellus or as Pax or Italia, and argued over for a century. That relief is the visual origin of nearly every subsequent European allegory of the fertile earth.
The Gaia hypothesis, and the borrowed name
In the early 1970s the chemist James Lovelock, with Lynn Margulis, proposed that the Earth's biosphere, atmosphere and oceans function as a self-regulating system, and his neighbour, the novelist William Golding, suggested he call it Gaia. The name did enormous work for the idea's public reach and enormous damage to its scientific reception, because it invited a teleological reading Lovelock spent decades denying.
It also produced a persistent modern picture of the Greek goddess as a benign, balancing, nurturing planetary intelligence. That is not the figure in Hesiod. Hesiod's Gaia is the one who supplies the weapon, hides the ambush, and when displaced by the winners produces something worse. She is a strategist, and she loses in the end — Typhon is beaten and the Olympian order holds — but nobody in the Theogony has a longer record of successful regime change.
Earth goddesses, real and invented
Is she the same as Rhea or Cybele?
They are distinct in the genealogies and overlap in function. Rhea is her daughter, wife of Cronus, mother of the Olympians. Cybele, the Phrygian mother of the gods with her lions and her ecstatic eunuch priests, was identified by Greeks with Rhea and sometimes with Gaia, and the composite "Great Mother" that appears in modern writing merges all three plus Demeter. The merging is ancient in places, but the sources do keep them apart where it matters, and Gaia is a generation older than any of them.
Is Gaia’s name Greek in origin?
Gaia or Gē has no secure etymology and is not obviously Indo-European, which is itself suggestive for a very old deity. The form Ge gives English geography, geology and geometry — literally earth-measuring, which is what surveying a flood-scoured field required. That family of words is her largest living legacy.
Is there a Gaia iconography at all?
Yes, though less often than her importance suggests. The characteristic type shows her half-emerged from the ground, visible only from the waist up, often handing over a child or reaching towards Zeus during the Gigantomachy — she appears on the Pergamon Altar frieze pleading for her sons. The half-buried pose is one of the neatest solutions in Greek art to the problem of depicting a deity who is the thing she is standing in.
Was there ever an earth-goddess religion that came before the Olympians?
The idea of a universal prehistoric Great Goddess cult overthrown by patriarchal sky-god invaders was extremely influential in the twentieth century, through Bachofen, Jane Harrison, Robert Graves and Marija Gimbutas, and it is no longer accepted in that form by most archaeologists — the evidence for a single unified goddess religion across prehistoric Europe does not hold up. What remains true and more modest is that Gaia is very old, that she holds oracular and chthonic functions the Olympians later took over, and that Greek myth remembers those takeovers.