Arethusa is a figure of Greek mythology, daughter of Nereo and Doride.

The god Alfeo, son of the god Oceanus, fell in love with her, spying her while she was swimming naked. Arethusa refused his attention, fleeing on the island of Ortigia, in Syracuse, where the goddess Artemide turned her into a fountain.

Zeus, touched by the pain of Alfeo, turned him into a river, thus allowing from the Peloponnese, in Greece, to travel all over the Ionian Sea to join the beloved source.

Even today the myth lives on the island of Ortigia, thanks to the so-called Fountain of Arethusa, a mirror of water that flows into the Great Harbour of Syracuse. In reality, Alfeo was a small river in Greece that make a quick trip to the surface and then disappear below ground. When the Greeks found the small spring near the source of Arethusa, they found the fanciful explanation to the disappearance of the river Alfeo in Greece, which would reappear on the surface in Sicily.