Are Neptune and Poseidon the Same God? Myths & History Made Easy

Learn the origin stories of the sea gods Neptune and Poseidon

Co-authored by Danielle Blinka, MA, MPA

Last Updated: February 10, 2023 References

Who is Neptune?

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Who is Poseidon?

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Similarities

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Differences

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Fun Facts

When you’re reading Roman and Greek mythology, it’s easy to see how Neptune and Poseidon are similar. Sometimes, people use their names interchangeably, even though they’re not the same god. Roman myths are based on Greek mythology, but the sea gods Neptune and Poseidon have some key differences. Read on to find out everything you need to know about Neptune and Poseidon—plus a few fun facts you can use to impress your friends.

Things You Should Know

Neptune is the Roman sea and freshwater god, while Poseidon is the Greek god of the sea.
The Greeks created Poseidon’s mythology first, so a lot of myths about Neptune are based on stories about Poseidon.
Poseidon is a more powerful and important god than Neptune because Greek culture was based around seafaring, while Rome pursued land-based conquests.

Section 1 of 5:

Who is Neptune?

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Neptune is the Roman god of freshwater and the sea. Even though Italy is surrounded by sea water, the capital city of Rome is landlocked. Because of this, Neptune started out as a freshwater god and later became a god of the sea as the Romans adopted myths from Greece. His parents are the god Saturn and the fertility goddess Ops, and he began his role as a water god by giving freshwater to the Romans.^{[1]
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Neptune first appeared in Roman mythology in 4 BCE. He's first mentioned over 1,000 years after Poseidon. This was about 400 years after the Roman empire began, so he wasn’t in the original Roman pantheon.^{[2]
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- Over time, the Romans adopted many of Poseidon’s traits into the mythology of Neptune, which is why the gods seem so similar.
- A pantheon is a set of gods from the same religion.
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The name “Neptune” comes from an Indo-European root word. There are 2 possible root words for his name. The first word is “neptu-,” which means “wet” and "moist." The other possible root word is “nebh,” which can mean “fog” or “cloud.” So, his name means something like "the moist one."

Section 2 of 5:

Who is Poseidon?

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Poseidon is the Greek god of the sea. Much of Greece is surrounded by sea water from the Aegean, Mediterranean, and Ionian Seas, as well as the Sea of Crete. Because of this, Poseidon is primarily a sea god. He got his position after drawing lots with his brothers Zeus and Hades, who became the gods of the sky and underworld, respectively. Their parents are Rhea and Cronus, who were Titans.^{[3]
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- When you study Greek mythology, Zeus, Poseidon, and Hades are basically the founders of the pantheon, along with their sisters Hera, Demeter, and Hestia.
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Poseidon predates Neptune. He was first mentioned during the Mycenaean period, which spanned between 1100 BCE and 1600 BCE. He remained an important god as Greece developed.^{[4]
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- Unlike other cultures, the Greeks based their gods on people, so they had lively tales about their exploits and vivid descriptions. Because they were so interesting, the Romans adopted these stories for their own mythology.
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The name “Poseidon” comes from Greek and Indo-European roots. The Greek word “posis,” which is based on the Indo-European word “pótis,” which can mean “lord,” “master,” or “husband.” The second root word is either “da,” which means “earth” or “dǎwon,” which means “water.” His name likely meant “master of the earth” or “master of the water.”^{[5]
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Section 3 of 5:

Similarities

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Both Neptune and Poseidon are gods of water who carry a trident. They have similar powers and share a lot of the same myths.^{[6]
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Research source} Many of Neptune’s attributes are directly based on Poseidon’s mythology, which is why the two gods are often mixed up. Over time, the pair became more and more alike.^{[7]
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- Many artistic depictions of the two gods, like sculptures and paintings, are named after both of them.
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They can both cause storms, shipwrecks, and earthquakes. As gods of the sea, they can stir up the waves and create massive weather events. Additionally, they can sink ships—or help them arrive safely. Despite being sea gods, they can also cause earthquakes by angrily striking the ground with their tridents.^{[8]
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- Like the sea, Poseidon and Neptune are depicted as being a bit moody, so they’re prone to anger. When they’re mad, they unleash their fury through storms or natural disasters.
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Since they both created horses, they also rule over them. Originally, the Romans worshiped a god named Consus as their horse god, but Neptune took over that role, likely to mirror Poseidon. As the patrons of horses, both gods received sacrifices of horses, who were drowned at sea.^{[9]
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Research source} Here are the myths about how each god created horses:
- Poseidon made the horse to impress his sister Demeter, an Earth goddess, after he fell in love with her. He modeled the horse off the waves of the ocean, making it the most beautiful creature he could envision. However, it failed to impress Demeter.^{[10]
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- Neptune fathered the first horses, including the flying horse Pegasus. Their mother was the gorgon Medusa. According to myth, Neptune assaulted Medusa in the goddess Minerva’s temple and impregnated her.^{[11]
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Section 4 of 5:

Differences

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Neptune and Poseidon have different origins. Greece was a seafaring society, so they revered Poseidon as the god of the sea. On the other hand, the Romans focused on building roads and undertaking land conquests, so the sea wasn’t as important to them. Neptune originated as the god of freshwater because it was far more important to the landlocked Roman cities.^{[12]
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- Neptune may originate from the Etruscan or Latium peoples who originally settled in Italy. The Etruscans had a water god named "Nepthuns" that may have originally inspired Neptune.^{[13]
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Poseidon is worshiped as 1 of the 3 top gods, while Neptune isn’t. In Greek mythology, Zeus, Poseidon, and Hades are the 3 most powerful gods. Because of this, Poseidon had temples throughout Greece and was widely worshiped. However, the same isn’t true of Neptune, who wasn’t one of the original Roman gods. He only had 1 temple and was mostly worshiped in areas near water.^{[14]
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- In Roman myth, the top 3 gods are typically Jupiter, Mars, and Minerva. Jupiter is the Roman version of Zeus, while Mars is the Roman version of Ares, the Greek god of war. To Romans, war and conquest were important, not sea travel.^{[15]
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  Research source} Minerva is the Roman goddess of wisdom, victory, law, and justice. She’s based on the Greek goddess Athena.^{[16]
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- Although Neptune doesn’t have a lot of temples, he did have shrines near freshwater sources.^{[17]
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Neptune is sometimes childless, while Poseidon has several kids. Neptune is partnered with Salacia, the goddess of the sea. In their mythology, the pair were initially childless, but their myths later incorporated some of Poseidon’s children.^{[18]
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Research source} On the other hand, Poseidon married Amphitrite, who was a nymph who became the goddess of the sea. He fathered 3 children with her, including the merman Triton.^{[19]
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- Poseidon also had children with multiple other goddesses, including the cyclops Polyphemus, whom Odysseus kills at the beginning of The Odyssey.
- Triton is probably the most well-known child of Poseidon, and he’s also sometimes attributed to Neptune. He’s also a sea god and acted as his father’s messenger.^{[20]
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Poseidon fought the titans, but Neptune didn’t. In Greek mythology, the titans originally ruled the Earth. Poseidon and his siblings are the sons of Cronus, the youngest Titan, and his sister-wife Rhea. In fear that his child will overthrow him, Cronus eats all of his kids, until Rhea hides Zeus. Once Zeus is old enough, he returns to serve as Cronus’ cupbearer and poisons him, causing Cronus to throw up his children, who became the Olympians. The Olympian gods and goddesses, led by Zeus, Hades, and Poseidon, fought the titans to gain control of the world.^{[21]
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- On the other hand, Neptune was originally based on the Etruscan god Nethuns, as discussed above.^{[22]
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- Sometimes Neptune’s origin is depicted a little closer to Poseidon’s. In that version, he and his siblings are all swallowed by their father Saturn because he fears his children will overthrow him. Their mother Ops saves Jupiter by giving Saturn a stone to swallow instead, and the stone makes him throw up the children. Then, the children team up to overthrow Saturn.^{[23]
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Section 5 of 5:

Fun Facts

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Neptune took on the traits of Poseidon over time. Originally, the Romans based Neptune on the Etruscan god of freshwater rivers and streams, Nethuns.^{[24]
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Research source} At first, they didn’t have a sea god, and their god had no physical description. As people migrated and the Romans traded with Greeks, they adopted the Greek mythology surrounding their gods and goddesses because it was more interesting. At that point, Neptune started to resemble the Greek sea god Poseidon.^{[25]
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- Neptune started adopting Poseidon’s characteristics around 399 BCE.^{[26]
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Neptune has a festival, but Poseidon doesn’t. The Romans celebrated Neptune in a festival called Neptunalia, which they held on July 23rd. They chose that day because it’s in the middle of summer, when droughts are more common.^{[27]
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Research source} During the festival, the Romans celebrated water and sacrificed a bull to Neptune so he’d give them more water.
- Neptunalia mostly consisted of drinking and partying.^{[28]
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Astronomers named the planet Neptune after the god. When they first found it, astronomers believed that the planet Neptune might control the oceans and tides, just like the moon. So, they named it after the god Neptune because he ruled the seas.^{[29]
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- All of the planets—and Pluto—in the Milky Way besides Earth are named after Roman gods. Early astronomers didn’t view Earth as a planet because they perceived it as the center of the universe.