In Greek myth, Poseidon's trident was forged by the cyclopes according to Pseudo-Apollodorus's Bibliotheke. Poseidon wields his trident on a number of occasions. Poseidon used his trident to strike a rock upon the hill of the Acropolis, producing a well of seawater, in what developed into a contest between him and Athena over possession of Attica. The well was later to be called the Erechtheis. There is further myth that Poseidon produced a horse by striking the earth with the trident, in order to bolster his claim, but there is no attestation for this among Greek writers. The alleged trident print on a rock and the sea well within the Erechtheion were witnessed by the geographer Pausanias while visiting Athens. In another myth, Poseidon creates a spring or springs with the strike of his trident to reward Amymone for her encounter with him. In a version of another myth Poseidon wields his trident to scare off a satyr who tries to rape Amymone after she mistakenly hits him with a hunting spear. There is also a myth where Poseidon touches the island of Delos with his trident, affixing it firmly to the sea floor. Another myth tells how Poseidon, enraged by sacrilegious behavior of Ajax the Lesser, splits with trident the rock to which Ajax was clinging. The oldest coins of Poseidonia from the 6th century BC depict trident wielded by Poseidon in his right hand, similar to Zeus's thunderbolt. An Attic red figurekylix from depicts Poseidon killing the GiantPolybotes with his trident.
Symbolism
According to the second and third Vatican Mythographer, Neptune's trident symbolizes the three properties of water: liquidity, fecundity and drinkability. The trident of Neptune was viewed by Roman scholar Maurus Servius Honoratus as three-pronged because "the sea is said to be a third part of the world, or because there are three kinds of water: seas, streams and rivers".
Modern scholarship
The view shared by Friedrich Wieseler, E. M. W. Tillyard and several other researchers is that Poseidon's trident is a fish spear, typical for coast-dwelling Greeks. According to Robert Graves, however, both Poseidon's trident and Zeus' thunderbolt were originally a sacred labrys, but later distinguished from each other when Poseidon became god of the sea, while Zeus claimed the right to the thunderbolt. According to competing proposal by H. B. Walters, Poseidon's trident is derived from Zeus' lotus sceptre, with Poseidon being Zeus in his marine aspect.