Pegasus

And again, Ceto bare to Phorcys the fair-cheeked Graiae, sisters grey from their birth: and both deathless gods and men who walk on earth call them Graiae, Pemphredo well-clad, and saffron-robed Enyo, and the Gorgons who dwell beyond glorious Ocean in the frontier land towards Night where are the clear-voiced Hesperides, Sthenno, and Euryale, and Medusa who suffered a woeful fate: she was mortal, but the two were undying and grew not old. With her lay the Dark-haired One in a soft meadow amid spring flowers. And when Perseus cut off her head, there sprang forth great Chrysaor and the horse Pegasus who is so called because he was born near the springs (pegae) of Ocean; and that other, because he held a golden blade (aor) in his hands. Now Pegasus flew away and left the earth, the mother of flocks, and came to the deathless gods: and he dwells in the house of Zeus and brings to wise Zeus the thunder and lightning. But Chrysaor was joined in love to Callirrhoe, the daughter of glorious Ocean, and begot three-headed Geryones.


- Hesiod, The Theogony, The Bestiary