Who Was Poseidon in Greek Mythology?
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Poseidon was the god of the sea, brother of Zeus, and one of the three rulers who divided the world between them. He was also the god of earthquakes and horses, which is a stranger combination than it first appears and tells you a lot about how the Greeks thought.
What Poseidon ruled
When the Titans were defeated, the three brothers divided the cosmos. Zeus took the sky, Hades took the underworld and Poseidon took the sea, with the land held in common between them.
That last detail matters. Poseidon's claim to the land was never settled, which is the source of several myths in which he competes with other gods for control of a city or region. He is a powerful god operating slightly outside his own domain, and it makes him restless.
Earthquakes and horses
Poseidon carried the title earth shaker, and the Greeks credited him with earthquakes. Living in a seismically active region, they connected the sea and the trembling ground as expressions of the same unpredictable power.
The link to horses is less obvious to modern readers. Poseidon was said to have created the first horse, and horses were associated with waves and with the sea's rolling motion. Sacrifices of horses into the sea are recorded in his worship.
The contest for Athens
The best known Poseidon story is his competition with Athena for the patronage of a new city. Poseidon struck the ground with his trident and produced a spring of salt water. Athena produced an olive tree.
The people judged the olive more useful and the city became Athens. Poseidon reacted badly, and in some versions flooded the plain in anger. This pattern repeats: Poseidon competes, loses and retaliates, which is a good summary of how the Greeks saw the sea.
Poseidon in the Odyssey
Poseidon drives much of the plot of the Odyssey. Odysseus blinds the cyclops Polyphemus, who is Poseidon's son, and the god spends the next ten years preventing him from reaching home.
The story is a useful window into Greek attitudes. For a seafaring people, the sea was essential and lethal, and its temperament could not be predicted or reasoned with. A god who holds a grudge for a decade over an insult to his son captures that relationship precisely.
How he was worshipped
Poseidon received serious attention from anyone whose life depended on water:
- •Sailors making offerings before voyages and after safe returns
- •Coastal cities building temples on prominent headlands
- •Horse breeders and cavalry honouring him
- •Communities in earthquake prone regions seeking protection
Poseidon and the Minotaur
One of Poseidon's more consequential interventions began with a gift. He sent King Minos of Crete a magnificent white bull as a sign of divine favour, expecting it to be sacrificed back to him.
Minos kept the bull and sacrificed a lesser one instead. Poseidon's revenge was indirect and devastating: he caused Minos's wife to fall in love with the bull, and the child of that union was the Minotaur. The labyrinth, Theseus, Daedalus and Icarus all follow from a single withheld sacrifice, which shows how tightly Greek myths interlock.
The takeaway
Poseidon in Greek mythology ruled the sea while also governing earthquakes and horses, and his repeated pattern of competing, losing and taking revenge reflected exactly how a seafaring people experienced the ocean.