Neigh, Neigh, Neigh
Of all the Greek legends the story of The Winged Horse, Pegasus is one of the most popular ones. Pegasus's origins are steeped in ancient Greek myth starting with the story of Acrisius, King of Argos who had a child, Danae, but desired a son to complete his life. Once he asked the oracle, he was displeased by its reply, telling him he will have no son but a grandson who would attempt to kill him. Afraid that the oracle's prediction might come true, he locked his daughter away, forbidding her to leave. Taking pity on the poor girl, Zeus king of the gods visited Danae in her room, and showered her in a blanket of gold coins if legend is to be believed, ravishing her. From this union between a mortal and a supreme god, a child is born to become a hero, Perseus. Discovering the tryst she had with a god such as Zeus, he sets them free, fearing retribution, they get rescued by Zeus who takes them to the island of Seriphos where the islands king Polydectes who found them, took an instant liking to Danae who when he asked her to marry him, refused, leaving him angry.
Once Perseus has grown up, Polydectes saw him as a love rival and thought up a plan to get rid of him; organizing a banquet in Danae's honor inviting in several of the island's men to ask for her hand in marriage, many bright presents for her, yet Perseus could not afford to match their riches. Perseus tells the king he would like to bring her a present of his own, and Polydectes mocked him, ordering him to bring the head of the Gorgon Medusa. Thinking it is too much of a task, he offers to take him up on the offer even though he fears he cannot do as he is asked.
Zeus hears his pleas and sends gods Hermes and Athena to help him out. Athena gave him her shield while Hermes lent him his sickle so he could hack off Medusa's head while looking at her reflection in Hermes' shield. Before he could complete the task Polydectes had given him, Hermes said he had to visit the Nymphs of the North Wind as was given one of his winged sandals and a hat of invisibility from Hades.
Perseus did as he was told, nearing where the Gorgons were, spotting Medusa, he hid from her gaze removing her head with one swift stroke, and bagged her serpent covered limb successfully before leaving for home. From the body of Medusa, Pegasus leapt as a beautiful winged horse that was ready to assist Perseus further in his endeavors.
In one story Perseus witnessed a woman bound to a rock, finding her name was Andromeda, her reason for being bound was that she was a sacrifice to the sea serpent, the kingdom hoping to placate it with the offering. Perseus used Medusa’s head to turn the monster to stone, and he and Andromeda had, by the time they had returned to see Danae fallen in love. Perseus though is shocked to find that Danae is still a prisoner of Polydectes, and ends her slavery by producing Medusa’s head from his bag, instantly petrifying his enemy to stone, freeing Danae. Even though the prophecy came true for Perseus to kill his grandfather, he eventually settled down with Andromeda, freeing Pegasus, his trustee steed to have another master.
Another hero found Pegasus soon enough, Bellerophon who travelled through the air in order to evade the fire-breathing Chimera, a huge composite beast whose head was that of a lion, the body of a huge goat, and the tail of a snake. Bellerophon killed the monster using a long spear, driving it into its neck, but Bellerophon had a high opinion of himself, ignoring the greatness of the gods on Olympus, making him Zeus’s sworn enemy who had him fly to Earth, losing his position as a hero, left to live the rest of his life as a poor man.
There were two different legends about Pegasus and how he came into being. It is believed that Posiedon the god of the sea might have had something to do with Pegasus coming to life, as the blood from Medusa's head dripped on the foam from the sea, merging to give birth. In the other one, is obviously the story where Pegasus came from the blood of Medusa when Perseus slew her.