Arion is a legendary horse (capable of supersonic speed and carried many heroes), which Poseidon begot by Demeter; for in order to escape from the pursuit of Poseidon, the goddess had metamorphosed herself into a mare, and Poseidon deceived her by assuming the figure of a horse. Demeter afterwards gave birth to the horse Arion and Despoine, who became a minor goddess whose primary function was looking after one of Demeter's temples..