Phlegon
In Roman Myth, Phlegon is one of the four winged horses of the sun. The poet Ovid lists Achton, Eous and Pyrios as the other horses. These four were harnessed daily to the chariot of the sun and driven across the heavens by the charioteer Phaethon.
John and Caitlin Matthews, The Element Encyclopaedia of Magical Creatures, 2013, Phlegon, p 371