In Greek mythology, Pegasus was an immortal winged horse, one of the two children of Poseidon and Medusa. Along with his brother, the golden-sworded Chrysaor, Pegasus sprang forth most miraculously from his pregnant mother’s neck after Perseus had beheaded her. He belonged to the Greek hero Bellerophon for some time, before being stabled by Zeus and tasked with drawing the chariot of his thunderbolts.

Pegasus and Water Springs
Hesiod says that Pegasus’ name originates in the Greek word for springs, pegae, since he was supposedly born near the springs of Ocean. But he was also associated with waters due to an extraordinary trait of his he had inherited from his father.