1 In lieu of an introduction
Some day (gods willing) I will write a proper article about Poseidon. For now, I am only collecting some pronouncements from the grammarians, as it seems to me that the ancient commentators on Homer and Vergil have been unusually successful in pinpointing his nature. (But even this material deserves a much better presentation than I have been able to give it.)
“When Jupiter, Neptune and Father Dis, the sons of Saturn and Ops, came to fight over the possession of the cosmos, they decided to divide the rule by lot. So it came about that Jupiter was allotted heaven, Neptune the seas, and Father Dis the underworld” (Servius auctus, On the Aeneid 1.139).
“These three deities, although they hold divided realms (regna), nevertheless seem to have mutual power over the whole realm, just as the elements themselves which they control are joined to each other by a certain physical relation (physica ratio). The deites’ sceptres also show this, since Jupiter uses a three-forked thunderbolt, Neptune the trident, and Pluto the threefold Cerberus (tricerberus)” (Servius, On the Aeneid 1.133).
“The Earth is common to all, and great Olympus” (Iliad 15.193); scholium: “Some think this means ‘common to the sons of Kronos’; others ‘common to the entirety of the gods’, so that we should honor all gods as overseeing human matters; others again say that he is referring to the four elements: Zeus to ether (i.e. ‘fire’), Poseidon water, Hades air; then the Earth, and in it, Mount Olympus par excellence, because as a mountain, Olympus is connected to the Earth.”
“Neptune […] is god of the waters” (Servius, On the Aeneid 7.691).
“Neptune presides over all rivers, springs and waters” (Servius auctus, On the Georgics 1.12).
“The one who furnishes watery substance (hygra ousia) is named Poseidon, from posis (‘drink’)” (D-Scholium on Iliad 15.18)
“The trident is assigned to Neptune because the sea is called the third part of the world by some; or because there are three kinds of waters, the sea, rivers and streams, and many say that Neptune presides (praeesse) over them all” (Servius auctus, On the Aeneid 1.138).
They sacrifice bulls “to the rivers and Poseidon, because the origin comes from moisture (hygron): ‘Oceanus, the origin of the gods’ [Iliad 14.201;302]” (Scholium on Iliad 23.147).
“Neptune, the ruler (dominator) over all the gods in the sea” (Servius, On the Aeneid 3.73).
“Earth-holder (gaiēokhos) and Earth-shaker (ennosigaios) are adjectives (epitheta) of Poseidon; and the one means ‘he who holds the Earth together’, the other ‘he who moves it’” (D-Scholium on Iliad 13.43).
“Poseidon is not the cloud-gatherer (nephelēgeretēs = Zeus); but in relation to humans, the gods wholly have the power over all things. Still, Odysseus in the following attributes the cause (of the clouds’ movement) to Zeus, following the opinion of the many” (Scholium on Odyssey 5.293).
“Poets are wont to give to the gods the appearance of the elements” (Servius, On the Aeneid 1.254)
“Vergil uses the (name of) the god to mean the waters” (Servius, On the Georgics 4.29).
“The poets often use Neptune to mean the sea” (Servius auctus, On the Aeneid 1.126).
“The scepter and spear of Poseidon is the trident” (Scholium on Iliad 13.59).
“It is assumed that there is a dwelling of Poseidon in the depth under the Aegean Sea, which is invisible to humans, just like those of the other gods on Mount Olympus, which also cannot be seen” (Scholium on Iliad 13.21).
“A bull for (the river) Alpheios, a bull for Poseidon” (Iliad 11.728); scholium: “The sacrifices are appropriate; he says bulls are sacrificed to rivers and to Poseidon because of the violent force of the waters.”
“Entirely black bulls” (Odyssey 3.6); scholium: “bulls because of the violent force of the sea, black because of the color of water in its depth.”
“Even numbers are proper to the dead; for this reason, they sacrifice nine (animals) to Poseidon” (Scholium on Iliad 23.171).
2 The Names of Poseidon
[Phoenician name of the Poseidon of Berytos is not known!]