In Greek mythology, Poseidon was said to be the father of the winged horse Pegasus.
Pegasus was born from the blood of Medusa after the hero Perseus beheaded her. In the best-known classical account, Medusa had been impregnated by Poseidon before her transformation into a monster. Pegasus therefore had Poseidon as his divine father, while Medusa was his mother.
The myth connects Pegasus with both the sea god and the monstrous Gorgon. After his birth, the winged horse became associated with the hero Bellerophon, who attempted to ride him against the Chimera. Bellerophon’s later attempt to reach Olympus ended in disaster, while Pegasus continued into divine tradition.
Pegasus is often mistakenly described as a son of Zeus because Zeus later used him in stories involving thunder and because the horse became strongly linked with the heavens. Another common mix-up is confusing Pegasus with Chrysaor, who was also born from Medusa after her death and was likewise connected with Poseidon.