People are often tempted to link aspects of oral tradition - and especially of old/ancient mythologies - to the concrete inspirations in the world. These approaches are almost always fruitless and can be lumped together under the term 'Euhemerism', a discredited school of mythological study which takes its name from the late 4th-century BCE Greek writer, Euhemerus.

There is a large complex of old European traditions that express links with water, horses, and a powerful male deity. The vast geographic manifestations of this motif - together with the antiquity of many of its expressions - hint at an early Indo-European complex of story and belief. More recent manifestations include the Scandinavian and other Northern European stories of a niccor, a water spirit that can manifest as an old man playing violin or as a horse who can lure children to ride on its back, charging back into the water to drown them. Many river names find roots in this word and its cognates.

From Poseidon to these more recent legends (to Tolkien's surging river that manifested as white horses), this complex of tradition is not likely linked to some prehistoric, central-Eurasian individual's musing that horses like to play on beaches.

edited to correct a typo; I had written "Modern recent manifestations" - I mean "More recent manifestations"