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Neptune, God of the Sea

You can click on any coin image to see the full coin.

The reverse of a bronze coin of Corinth showing a trident The reverse of a holed bronze coin of Corinth showing an ornamented trident.
The obverse of a bronze coin of Macedonia showing the head of Poseidon with a trident The obverse of a bronze coin of Macedonia showing the head of Poseidon with a trident.

Before Neptune there was the Hellenistic god Poseidon, one of the three senior gods, brother of Zeus and Hades. When the world was divided between these three, by lot, Zeus received the earth, Hades the underworld, and Poseidon became lord of the sea. He was also known as the earth-shaker, creator of earthquakes.

He appeared on many Hellenistic coins, including the bronze of Macedonia on the right. As a senior deity, he was shown mature and bearded. He always carried a trident, and it is over his shoulder on this coin. In fact the trident often appeared alone, as his symbol, as on the coin on the far right from Corinth, where he was the chief deity of the city.

In Athens, he came second to Athena in a contest to see who the city would accept as its patron. The salty spring he produced was far less useful than Athena's olive tree. His conflict with Athena also appeared in the myth of Medusa. He ravished the then beautiful Medusa in the grounds of Athena's temple, which aroused her to anger and caused her to curse Medusa with ugliness and deadliness. You may think that this was not very fair to Medusa, but fairness is not a distinguishing feature of Greek myths.

The obverse of a fake Roman Republican denarius of showing Neptune The obverse of a fake Roman Republican denarius of showing Neptune.

The Romans developed a deity they called Neptune, who seems to have evolved from the Etruscan god Nethuns. Both of these were close equivalents of the Hellenistic Poseidon, but as usual with the Roman pantheon, not completely identical. A temple to Neptune was built in Rome in 25 BCE, near the Circus Flaminius, a multi-purpose venue south of the Field of Mars. He had a two-day festival of obscure and archaic origins, called Neptunalia, on which tents or huts were made from foliage and the branches of bushes.

On the left is a (modern copy of) a Roman Republican denarius of Sextus Pompey, 100 to 150 years later than the Macedonian coin above, but with an almost identical image. Sextus Pompeius Magnus Pius was the youngest son of the famous Pompey the Great, who fought unsuccessfully against Julius Caesar.

The youngest Pompey also fought Caesar, and later retreated to Sicily, where for many years he had a successful base. This denarius may have been struck to celebrate a naval victory over Augustus. By this time, Neptune was established as the deity to be thanked for naval victories. In fact, Sextus Pompey called himself "son of Neptune."

The reverse of a billon denarius of Gallienus showing Neptune The reverse of a billon denarius of Gallienus showing Neptune with one foot on a prow.
The reverse of a silver denarius of Septimius Severus showing Neptune The reverse of a silver denarius of Septimius Severus showing Neptune with one foot on a rock.

Sextus Pompey was eventually defeated by Marcus Vipsanius Agrippa, a military genius who was a faithful friend and ally of Augustus, the first Roman emperor, and who had no small part in his rise to supreme power. Agrippa had many victories, including the naval Battle of Actium which sealed the fate of Cleopatra and Mark Antony. He dedicated a temple to Neptune in honour of that victory; the Basilica Neptuni, on the Campus Martius (the Field of Mars). This was Neptune's second temple in the city.

The reverse of a copper as of Gaius Caligula showing Neptune holding a dolphin The reverse of a copper as of Gaius Caligula showing Neptune holding a dolphin.

Later, Agrippa's grandson, the emperor Gaius (known to us as Caligula), put him on a copper coin with a Neptune reverse. That reverse is on the left. Agrippa was shown with a rostral crown, made up of miniature prows of war galleys. On the reverse, a nude Neptune leans on his trident and holds a dolphin on his outstretched arm. If this is not totally clear on this example, you can see the same dolphin on some of the coins shown below. The trident always meant Neptune, and the dolphin always signalled a connection with the sea. You can click any of these images to see the whole coin.

The coin above left is a denarius of Septimius Severus from 210 CE. On it, Neptune stands with one foot on a rock, leaning forward slightly with one hand on his bent knee. His tall trident is held behind him. Severus was in Britain when this coin was struck, so the reason for this type is not obvious. Gallienus struck an antoninianus with an almost identical image at Antioch 57 years later, shown on the right; but this time, Neptune's foot is on the miniaturised prow of a galley.

The reverse of a billon antoninianus of Postumus showing Neptune holding a dolphin The reverse of a billon antoninianus of Postumus showing Neptune holding a dolphin.
The reverse of a bronze coin of Elagabalus showing Poseidon in a temple The reverse of a bronze coin of Elagabalus showing Poseidon in a temple.

On the right is a provinical coin of Elagabalus from 218-222 CE, showing Neptune in a temple. He is in a similar pose to the Severus coin, but has a small dolphin on his outstretched arm like the figure on the Agrippa coin shown above. The dolphin is a little clearer on this coin.

It is even more so on the next, an antoninianus of Postumus from 262 CE. Here, his posture is more stylised, with elegantly curved legs rather than the foot-up stance on the last two coins, and a long, long forefinger delicately pressed to the shaft of the trident. The prow of a boat is sketched in front of him.

A galley on the reverse of a copper as of Marcus Aurelius. A galley on the reverse of a copper as of Marcus Aurelius.

Next is a coin with a reference to Neptune as a protective deity. It commemorates the return of Marcus Aurelius from a sea voyage in which his ship encountered a dangerous storm. The person in the steersman's hut on the left is actually Neptune, with his foot up in the typical position and a dolphin on his outstretched arm.

The standard reference says he has his foot on a rock, which would not normally be found on a ship! That is the stance shown on the denarius of Septimius Severus above, copied to this coin regardless of the surroudings he has been placed in. But that typical stance makes it easier to recognise Neptune on this much smaller scale.

The reverse of a billon antoninianus of Gallienus showing a hippocamp The reverse of a billon antoninianus of Gallienus showing a hippocamp.

By placing him in charge of the rudder, the engraver gives him credit for safely steering the ship home. The legend dedicates the coin to the happiness of the emperor.

Here's Neptune as a protector again. The emperor Gallienus had to deal with invasions, usurpers and parts of his empire breaking away. Around 267 CE, when he was dealing with an invasion of Goths, he produced a range coins showing animals, and asking the protection of the deities associated with them.

This one shows a hippocamp, and the legend, NEPTVNO CONS AVG, names Neptune as "protector of the Emperor." The hippocamp was a mythical sea monster, with a horse's front end and a fishy rear, here shown with a many-pronged tail. There are more monsters on my "monsters on ancient coins" page.

A feature of this coin is the odd way the letter N is carved, as three vertical strokes, the central stroke sometimes having a very slight inclination. This is common on the coins of Gallienus and his wife Salonina.

The reverse of a silver denarius of Titus showing Neptune The reverse of a silver denarius of Titus showing Neptune holding an aplustre.

The last coin on this page is a denarius of Titus, from 73 CE, early in the history of the Imperium. It shows a slightly different Neptune. His stance is the one we are now familiar with, but his foot is on a globe rather than a rock, showing the breadth of his dominion. In his right hand he is holding an aplustre, a fancy decoration which was mounted high on the stern post of a galley. (It is sometimes erroneously called an acrostolium in descriptions of this coin type.) He is holding a tall sceptre rather than a trident. Because you can't see the top of this sceptre, I looked around for other examples, expecting to see the familiar trident; but, exceptionally, it's not there!

But the legend makes it definite that this is Neptune. It is NEP RED, identifying the figure as the aspect of Neptune who ensures the safe return of the emperor from a sea voyage.

This particular coin is not listed in any of the normal reference works, so is quite scarce; but it is very much like a common coin which is listed, so it's not particularly valuable. The difference is only one word in the obverse legend.


The content of this page was last updated on 19 July 2009

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