Pegasus is a winged horse in Greek mythology, usually depicted as a white stallion. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. Pegasus was the brother of Chrysaor, both born when their mother was decapitated by Perseus. Greco-Roman poets wrote about his ascent to heaven after his birth and his obeisance to Zeus, who instructed him to bring lightning and thunder from Olympus.
Bellerophon riding Pegasus and slaying the Chimera, central medallion of a Gallo-Roman mosaic from Autun, Musée Rolin, 2nd to 3rd century AD.
Silver denarius of Domitian with Pegasus on the reverse, dated 79–80 AD
Pegasus, as the horse of Muses, on the roof of Poznań Opera House (Max Littmann, 1910)
Pegasus on ancient cup of Marlik
Poseidon is one of the Twelve Olympians in ancient Greek religion and mythology, presiding over the sea, storms, earthquakes and horses. He was the protector of seafarers and the guardian of many Hellenic cities and colonies. In pre-Olympian Bronze Age Greece, Poseidon was venerated as a chief deity at Pylos and Thebes, with the cult title "earth shaker"; in the myths of isolated Arcadia, he is related to Demeter and Persephone and was venerated as a horse, and as a god of the waters. Poseidon maintained both associations among most Greeks: he was regarded as the tamer or father of horses, who, with a strike of his trident, created springs. His Roman equivalent is Neptune.
The Poseidon of Melos, a statue of Poseidon found in Milos in 1877
Poseidon greeting Theseus (on the right). Detail, Attic red-figured calyx-krater by Syriscos Painter, 450-500BC from Agrigento. BnF Museum (Cabinet des médailles), Paris
Poseidon pursuing a woman, probably by Achilleus painter, 480-450BC. Metropolitan Museum of Art, Manhattan NY
Statue of Poseidon in Germany by Johann David Räntz and Lorenz Wilhelm Räntz (1760).