Pegasus is one of the best known fantastical as well as mythological creatures in Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

. He is a winged divine horse, usually white in color. He was sired by Poseidon

Poseidon

Poseidon was the god of the sea, and, as "Earth-Shaker," of the earthquakes in Greek mythology. The name of the sea-god Nethuns in Etruscan was adopted in Latin for Neptune in Roman mythology: both were sea gods analogous to Poseidon...

, in his role as horse-god, and foaled by the Gorgon

Gorgon

In Greek mythology, the Gorgon was a terrifying female creature. The name derives from the Greek word gorgós, which means "dreadful." While descriptions of Gorgons vary across Greek literature, the term commonly refers to any of three sisters who had hair of living, venomous snakes, and a...

 Medusa

Medusa

In Greek mythology Medusa , " guardian, protectress") was a Gorgon, a chthonic monster, and a daughter of Phorcys and Ceto. The author Hyginus, interposes a generation and gives Medusa another chthonic pair as parents. Gazing directly upon her would turn onlookers to stone...

. He was the brother of Chrysaor

Chrysaor

In Greek mythology, Chrysaor , the brother of Pegasus, was often depicted as a young man, the son of Poseidon and Medusa. However, Chrysaor is sometimes said to be a giant or a winged boar. Chrysaor and his brother, the winged horse Pegasus, were not born until Perseus chopped off Medusa's head...

, born at a single birthing when his mother was decapitated by Perseus. Greco-Roman poets write about his ascent to heaven after his birth and his obeisance to Zeus

Zeus

In the ancient Greek religion, Zeus was the "Father of Gods and men" who ruled the Olympians of Mount Olympus as a father ruled the family. He was the god of sky and thunder in Greek mythology. His Roman counterpart is Jupiter and his Etruscan counterpart is Tinia.Zeus was the child of Cronus...

, king of the gods, who instructed him to bring lightning and thunder from Olympus.