Poseidon

Poseidon is one of the three chief Olympian gods, ruling the seas after the Titans' defeat. He is known for his volatile temperament, his trident, and his rivalry with Athena over the patronage of Athens, a contest he lost and resented for the rest of the tradition.

By Mythographia Editorial Team Reviewed by Mythographia Editorial Team Updated 2026-09-09

What does the name "Poseidon" mean? →

Core Myth

Poseidon was one of the six children of the Titans Cronus and Rhea, swallowed at birth like his siblings and freed when Zeus overthrew Cronus. After the Titanomachy, Homer has Poseidon describe how the three brothers cast lots for the world: Zeus won the sky, Poseidon the sea, and Hades the world below, with earth and Olympus left common to all three, a point Poseidon uses in the Iliad to insist he answers to no one, Zeus included, in his own domain. He dwelt in a golden palace beneath the waves and wielded his iconic trident, which could cause earthquakes and summon or calm storms at will. His best-known contest is with Athena for the patronage of Attica. Apollodorus records that Poseidon struck the Acropolis with his trident to produce a saltwater spring, while Athena planted the first olive tree; Zeus appointed the twelve gods to judge between the two gifts, and they ruled for Athena on the testimony of King Cecrops, who had witnessed her planting first. Poseidon's resentment at the loss recurs across the tradition: he floods the Thriasian plain in retaliation in one version of the story, and his hostility toward Athenian heroes in other myths is sometimes read as a continuation of this old grudge.

How did Poseidon end up ruling the sea instead of the sky or underworld?

After the Titanomachy, the three sons of Cronus cast lots for the world, as Poseidon himself explains in the Iliad: Zeus won the sky, Poseidon the sea, and Hades the world below, with earth and Olympus held in common. Poseidon treats this as making him Zeus's equal in his own sphere rather than his subordinate, a point he makes explicitly when Zeus tries to give him orders through a messenger.

Homer, Iliad 15.187-193

Why did Poseidon lose the contest for Athens to Athena?

Poseidon struck the Acropolis with his trident and produced a saltwater spring; Athena planted the first olive tree. Zeus set the twelve Olympian gods to judge between the two gifts, and King Cecrops of Athens testified that Athena had planted hers first, which decided the verdict in her favor. The city took her name rather than his.

Apollodorus, Library 3.14.1

Why was Poseidon so hostile to Odysseus in the Odyssey?

Odysseus blinded Poseidon's son, the Cyclops Polyphemus, while escaping his cave, and then made the mistake of shouting his own name back at the wounded Cyclops as his ship pulled away. Polyphemus used that name to call down a curse from his father, asking that Odysseus reach home late, having lost all his men, and find trouble waiting there - a curse the rest of the Odyssey largely fulfills.

Homer, Odyssey 9.526-536

Did Poseidon ever fight on the losing side in a war among the gods?

In the Iliad's Theomachy, the gods split into factions to support either the Greeks or the Trojans, and Poseidon backs the Greeks. He faces Apollo directly on the battlefield but the two withdraw from the fight without striking a blow, unlike some of the other divine pairings, since Apollo declines to come to real blows with his uncle over mortals not worth a quarrel between gods.

Homer, Iliad 21.435-460

Is Poseidon's temper connected to earthquakes as well as storms?

Yes - his epithet Earth-Shaker (Ennosigaios) is used throughout Homer specifically for his power to shake the ground, distinct from his control of the sea itself, and ancient audiences associated seismic activity with his anger or his physical passage across the earth. The trident functions as the instrument for both powers in the tradition, striking rock to split earth or open springs just as it stirs or calms the sea.

Homer, Iliad 20.57-66

Later Traditions

Poseidon's temper appears repeatedly outside this one contest. He is the god behind Odysseus's decade of wandering in the Odyssey, punishing him for blinding his son the Cyclops Polyphemus, and he contests Athena's favor again in myths involving other cities and heroes. In Roman religion he was identified with Neptune, whose own cult grew increasingly tied to naval power as Rome's fleets expanded.

Lineage

See the full family tree

11 recorded relations, each with the ancient line behind it.

Parents

Kronos Hesiod, Theogony 453-458
Kronos swallowed each child at birth; Zeus alone escaped and later forced the others back up.
Rhea Hesiod, Theogony 453-458

Siblings

Children

Pegasus Hesiod, Theogony 278-283
Polyphemus Homer, Odyssey 9.412-419
Poseidon's grievance for his blinded son drives the wanderings of Odysseus.
Theseus Apollodorus, Library 3.15.7
disputed
Disputed parentage. Some sources name Aigeus of Athens as the father; Aigeus is not yet in the corpus.
Triton Hesiod, Theogony 930-933
Hesiod names Triton as the son born of Poseidon and Amphitrite, living with both parents in their golden undersea palace.

Also Connected

6 recorded connections, each with the ancient line behind it.

Connected

Amphitrite Hesiod, Theogony 930-933
Poseidon marries the Nereid Amphitrite, and together they have a son, Triton, who lives with them in their undersea palace.
Boreas Homer, Odyssey 5.282-296
Angered at Odysseus, Poseidon rouses all four cardinal winds together, Boreas among them, to wreck his raft.
Geryon Hesiod, Theogony 270-294
Geryon's father Chrysaor, not yet a separate entity in this corpus, was said to be Poseidon's son by Medusa - the sea god's bloodline lies behind Geryon's far-western, ocean-edge myth.
Proteus Homer, Odyssey 4.349-370
Homer's Odyssey calls Proteus "the servant of Poseidon," tending his seals near the Egyptian island of Pharos, a subordinate role rather than a stated parentage.
Thetis Apollodorus, Library 3.13.5
Poseidon rivaled his brother Zeus in courting Thetis until the same prophecy that turned Zeus away made him withdraw as well.
Triton Ovid, Metamorphoses 1.330-342
Distinct from the parentage the two also share: in Ovid's account of Deucalion's flood, Neptune personally commands Triton to sound his conch shell so its blast can recall the receding floodwaters, a specific act of service rather than a restatement of Triton's birth.