Greece

ἱππόκαμπος (Greek)

The hippocampus or hippocamp,  often called a sea-horse in English, is a mythological creature shared by Phoenician, Etruscan, Pictish, Roman and Greek mythology, though its name has a Greek origin.

In the Iliad, Homer describes Poseidon, god of horses, earthquakes, and the sea, driving a chariot drawn by brazen-hoofed horses over the sea's surface, and Apollonius of Rhodes, describes the horse of Poseidon emerging from the sea and galloping across the Libyan sands.

This compares to the specifically "two-hoofed" hippocampi of Gaius Valerius Flaccus in his Argonautica: "Orion when grasping his father’s reins heaves the sea with the snorting of his two-hooved horses." In Hellenistic and Roman imagery, however, Poseidon (or Roman Neptune) often drives a sea-chariot drawn by hippocampi. Thus, hippocampi sport with this god in both ancient depictions and much more modern ones, such as in the waters of the 18th-century Trevi Fountain in Rome surveyed by Neptune from his niche above.