Poseidon wields his trident on a number of occasions. He 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. When he lost, Poseidon used the trident to dry out the land so they had no water. The well was later to be called the Erechtheis. There is further myth that Poseidon (Neptune) 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.[b]
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 figure kylix from c. 475 BC depicts Poseidon killing the Giant Polybotes with his trident.
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".
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 a competing proposal by H. B. Walters, Poseidon's trident is derived from Zeus' lotus sceptre, with Poseidon being Zeus in his marine aspect.
In present times Poseidon's trident is a recurring symbol. It appears on the coat of arms of Liverpool City Council, on the seal of the Greek Navy and on the crest of the Delta Delta Delta sorority. It is a recurring motif in the US military, being featured on the crest of the United States Navy SEALs and on the badge of USS John S. McCain. A series of American fleet ballistic missiles Trident is named after Neptune's trident, as well as Operation Neptune Spear.
The personification of Great Britain, Britannia is depicted with the trident of Poseidon as a symbol of naval power. The broken tip of the trident appears on the flag of Barbados. In this instance, the reference is to its use as Britannia's trident, broken to symbolise the end of Britain's colonial rule.
The trident also appears multiple times in popular culture. Poseidon's trident is owned by King Triton (Poseidon’s son) in Disney’s 1989 animated film The Little Mermaid and its sequels and spinoffs. Poseidon's Trident is a magical artifact with destructive powers in Michael Livingston's 2015 historical fantasy novel The Shards of Heaven. Jack Sparrow, aided by Henry Turner, seeks the Trident of Poseidon in the film Pirates of the Caribbean: Dead Men Tell No Tales (2017).
- The Cyclopes also provided Zeus his thunderbolt according to this passage in Bibliotheke.
- Pausanias wrote that the sea well gave forth the sound of waves when the south wind blew.
- Pseudo-Apollodorus, Bibliotheke 1.2. Frazer tr. (1921), 1:11;text version via Perseus Project.
- Schmitz, Leonhard (1870). "Cyclopes". In Smith, William (ed.). Dictionary of Greek and Roman Biography and Mythology. Vol. 1. p. 909.. "Cyclopes" via Perseus Project.
- March, Jennifer R. (2014). Dictionary of Classical Mythology. Oxbow Books. p. 115. ISBN 978-1782976356.
- Pseudo-Apollodorus, Bibliotheke 3.14. Frazer tr. (1921), 2:79 and note 2; text version via Perseus Project.
- Hurwit, Jeffrey M. (1999). The Athenian Acropolis: History, Mythology, and Archaeology from the Neolithic Era to the Present. Cambridge University Press. p. 32. ISBN 978-0-521-41786-0.
- Virgil, Georgics 1.12ff apud Frazer tr. (1921), 2:79 and note 2.
- Frazer tr. (1921), 2:79 and note 2.
- Pausanias, Description of Greece 1.26.
- Robin Hard (2004). The Routledge Handbook of Greek Mythology: Based on H.J. Rose's "Handbook of Greek Mythology". Psychology Press. p. 235. ISBN 0415186366.
- Trudy Ring; Robert M. Salkin; Sharon La Boda, eds. (1995). International Dictionary of Historic Places: Southern Europe. Taylor & Francis. p. 180. ISBN 1884964028.
- Roman, Luke; Roman, Monica (2010). Encyclopedia of Greek and Roman Mythology. Infobase Publishing. p. 418. ISBN 978-1438126395.
- Brumble, H. David (2013). Classical Myths and Legends in the Middle Ages and Renaissance: A Dictionary of Allegorical Meanings. Routledge. p. 243. ISBN 978-1136797385.
- Quiggin, E. C. (2012). Essays and Studies Presented to William Ridgeway: On His Sixtieth Birthday - 6th August 1913. Cambridge University Press. pp. 189, 191. ISBN 978-1107605565.
- Robert Graves (2014). "46". The Greek Myths. Anne Books. ISBN 978-6155530814.
- "Trident II D-5". Atomic Archive. Retrieved 19 March 2015.
- "History". Maserati. Retrieved 8 Jan 2016.
- "The Shards of Heaven by Michael Livingston". Publishers Weekly. Retrieved January 29, 2016.
- "Review: The Shards of Heaven by Michael Livingston". Kirkus Reviews. September 3, 2015. Retrieved January 29, 2016.