Who is Poseidon? Guide to the Greek God of the Sea

Poseidon rules the sea, and the sea is not calm. He is the god of storms at sea, of earthquakes on land, of the horses that come out of the surf and the waves that swallow ships. He is the middle brother of the three sons of Cronus, and he was given the sea when the world was divided. He has never seemed entirely content with it. Most of his stories are about the fights he loses to other gods for possession of cities and territories, and about the elaborate revenge he takes on mortals who cross him.

Key Takeaways

Poseidon is the Greek god of the sea, earthquakes, and horses, and one of the twelve Olympians.
He is a son of Cronus and Rhea, brother of Zeus and Hades, and one of the three brothers who divided the cosmos by lot after the Titans were defeated.
His weapon is the three-pronged trident, forged by the Cyclopes; with it he causes storms, earthquakes, and springs of water.
His wife is Amphitrite, a sea-nymph; his children include Triton, Pegasus, and the Cyclops Polyphemus.
He is famously vindictive when crossed. He pursues Odysseus for ten years after Odysseus blinds his son Polyphemus.
He lost the contest for Athens to Athena when the city chose her olive tree over his saltwater spring, and lost the contest for other cities as well.
His Roman equivalent is Neptune, whose worship absorbed many of Poseidon’s stories directly.

Who is Poseidon?

Poseidon is the Greek god of the sea, earthquakes, storms, and horses. He is one of the twelve Olympians and one of the three brother gods who divided the world after the war against the Titans.

Definition - Poseidon

The Greek god of the sea, earthquakes, and horses. Poseidon is the son of Cronus and Rhea, brother of Zeus and Hades, and one of the twelve Olympians. He wields the three-pronged trident and rules from a palace beneath the sea. His Roman equivalent is Neptune.

His domain seems broad in a specific way: it is the domain of the things the Greeks most feared. Storms at sea drowned sailors. Earthquakes destroyed cities. And the horse, before it was fully domesticated, was a wild animal that killed as often as it served. Poseidon governs the border zones between what the Greeks could control and what they could not, and his character in the myths reflects that. He is powerful, unpredictable, easily offended, and difficult to appease.

Poseidon’s rise to power

Poseidon is one of the six children of the Titans Cronus and Rhea. Cronus, fearing a prophecy that one of his children would overthrow him, swallowed each one at birth. Zeus, the youngest, escaped this fate when his mother Rhea hid him and gave Cronus a stone to swallow instead.

When Zeus came of age, he freed his siblings. Poseidon fought beside his brothers in the Titanomachy - the ten-year war against the Titans - and helped defeat them. After the victory, the three brothers drew lots to divide the cosmos. Zeus took the sky. Poseidon took the sea. Hades took the underworld. The earth and Mount Olympus were held in common. Read Zeus’s rise to power and the Titanomachy.

The Greek tradition treats this division as final but not entirely satisfying to Poseidon. Zeus, ruling from Olympus, was the visible king. Poseidon, ruling from beneath the sea, was less seen. He rarely comes to Olympus in Greek myth, but when he does, he asserts himself.

Poseidon and the horse

Poseidon’s association with horses is one of the oldest features of his mythology, older than his role as sea god in some scholarly reconstructions. He was worshipped as Poseidon Hippios - Poseidon of the Horse - in many parts of Greece.

The tradition holds that Poseidon created the first horse. Some versions say he made it as a gift for humanity. Others say he made it in an unsuccessful attempt to woo Demeter, who fled from him in the form of a mare and gave birth, after Poseidon caught her in the form of a stallion, to the horse Arion. Read Poseidon’s creation of the horse.

Poseidon also fathered the winged horse Pegasus, born from the neck of Medusa when Perseus beheaded her, since Poseidon had lain with Medusa in Athena’s temple - one of the acts that had caused Athena to transform Medusa in the first place.

The connection between the god of earthquakes and the god of horses is not accidental. Both involve pounding rhythms, both come suddenly, and both, uncontrolled, can be lethal.

The contest for Athens and other cities

The most famous story of Poseidon losing is the contest for Athens.

When the city was founded, both Poseidon and Athena claimed it as patron. Each was invited to offer the city a gift. Whichever gift was judged more useful would win the patronage.

Poseidon struck the ground of the Acropolis with his trident. Saltwater welled up in a spring. It was dramatic. It was salt water.

Athena struck the ground with her spear. An olive tree grew. The Athenians could eat the olives, press them for oil, burn the wood, and trade the produce across the Mediterranean. They chose Athena. The city took her name. Read Athena’s contest with Poseidon for Athens and Poseidon and the founding of Athens.

Poseidon lost similar contests elsewhere. He fought Helios for the possession of Corinth and won only the isthmus, not the citadel. He fought Hera for Argos and lost, and in revenge dried up the region’s rivers. The pattern is consistent. Poseidon competes for territory and often does not win, and when he does not win, he tends to react by punishing the land or its people.

Poseidon and the Trojan War

Poseidon has an unusually complicated role in the Trojan War, and it goes back to a personal grudge against the city.

Long before the war, Poseidon and Apollo had been punished by Zeus and forced to serve the mortal king Laomedon of Troy for a year. They built the walls of Troy for him. When the year was over, Laomedon refused to pay them. Poseidon sent a sea monster against the city in retaliation, and Apollo sent a plague. Read Poseidon and the walls of Troy.

Because of this, Poseidon fought on the Greek side in the Trojan War. He did not forgive Troy. He worked to bring the city down.

He also, however, held a grudge against Odysseus for reasons unrelated to the war itself. Odysseus, on his way home, had encountered the Cyclops Polyphemus - Poseidon’s son - and blinded him to escape from his cave. Poseidon spent the ten years of Odysseus’s homeward journey punishing him with storms, shipwrecks, and delays. This grudge is the driving force of much of Homer’s Odyssey. Read the conflict between Poseidon and Odysseus, Poseidon’s role in the Trojan War, and Odysseus’s journey home.

The Greek tradition treats these punishments as characteristic of Poseidon. Zeus punishes with justice, in principle. Poseidon punishes with reach and duration, and his memory is very long.

Poseidon’s family

Poseidon’s wife is Amphitrite, a sea-nymph whom he wooed with the help of the dolphin. She lives with him in a palace beneath the sea. Their son is Triton, the merman with the conch-shell horn whose sound calms or agitates the sea.

Poseidon has many other children by many other mothers, including monsters and heroes in roughly equal measure. His children include the winged horse Pegasus, the Cyclops Polyphemus, the giant Antaeus (who could not be defeated as long as he touched the ground), the hero Theseus (in some traditions), the horse Arion, and many others. His monstrous children reflect his own tendency toward the wild and unregulated; his heroic children are among the most physically formidable in Greek myth.

Poseidon compared to other sea gods

Sea gods appear in every maritime tradition, and Poseidon is one of the most fully developed.

Tradition	Sea god	Attributes	Notes
Greek	Poseidon	Trident, horses, earthquakes	Brother of Zeus and Hades
Roman	Neptune	Trident, horses	Directly cognate to Poseidon
Norse	Njord	Wind and calm sea	Prosperity-giving, not stormy
Norse	Aegir	Storms and deep sea	The counterpart of Njord’s calm
Japanese	Ryujin	Dragon king of the sea	Rules from an underwater palace, similar to Poseidon
Yoruba	Olokun	Depth and wealth of the sea	Sovereign of the deep waters

The parallel with the Japanese Ryujin is worth noting. Both rule the sea from underwater palaces, both have daughters who marry mortal heroes, and both control the tides. The Greeks and Japanese never had contact in classical antiquity, so the parallel is convergent rather than derived.

Read the stories

Poseidon appears throughout Greek myth. Some entry points:

Poseidon is the god the Greeks propitiated before sailing, the god they blamed after a shipwreck, and the god they feared when the ground shook. He is not the god they wanted to know personally. He is the god of everything a Mediterranean people needed and could not master, and the tradition preserves him as he was: powerful, resentful, and permanent.

Frequently Asked Questions

What is Poseidon the god of?

Poseidon is the Greek god of the sea, earthquakes, and horses. His sphere covers storms at sea, the wild ocean, the shaking of the earth, and horses (both as creators and as the god of horsemanship). He was worshipped as Poseidon Hippios - Poseidon of the Horse - as much as Poseidon of the Sea in many parts of Greece.

Who is Poseidon’s wife?

Amphitrite, a sea-nymph. Poseidon wooed her with the help of the dolphin (which brought her to him when she initially fled). She lives with him in a palace beneath the sea, and their son is Triton, the merman with the conch-shell horn. Poseidon has many other lovers and children besides Amphitrite, both mortal and divine.

What is Poseidon’s weapon?

The trident, a three-pronged spear forged for him by the Cyclopes when Zeus freed them from Cronus’s prison. With the trident Poseidon causes storms at sea, shatters cliffs, causes earthquakes, and produces springs of water when he strikes the earth. The trident became so identified with Poseidon that it appears on Greek coins as shorthand for the god.

Why does Poseidon hate Odysseus?

Because Odysseus blinded Poseidon’s son, the Cyclops Polyphemus. When Odysseus and his crew were trapped in Polyphemus’s cave on the way home from the Trojan War, they escaped by getting the Cyclops drunk and driving a burning stake into his single eye. Polyphemus prayed to his father Poseidon for vengeance, and Poseidon spent the next ten years punishing Odysseus with storms, shipwrecks, and delays, keeping him from reaching Ithaca.

Is Poseidon the same as Neptune?

Yes, in essence. Neptune is the Roman equivalent of Poseidon, ruling the same sea with the same trident and the same character. The Romans identified Neptune with Poseidon early in their contact with Greek culture and adopted most of the myths directly, translating names but keeping the stories. Neptune retained the horse association as well and was worshipped as Neptunus Equester (Neptune of the Horse).

Why did Poseidon lose the contest for Athens?

He offered the wrong gift. When Poseidon and Athena both claimed the newly founded city, each was invited to offer it a gift. Poseidon produced a saltwater spring by striking the ground with his trident - impressive, but useless for a city that needed to drink. Athena produced an olive tree, which the Athenians could eat, press for oil, burn, and trade. They chose Athena. Poseidon lost, and the city took her name.