Phaethon son of the sun god bragged to his friends of his lineage. The refused to believe him so Phaathon asked his father to grant him one request. Helios swore he'd give his son anything he wished. Phaethon wanted to drive his father's chariot of fire. Helios was hesitant to grant the desire but had no choice since he had given his word.

Phaethon was inexperiences at driving, which the horses soon caught light of. They first flew too high burning a streak across the sky, known as the Milky Way. The Earth was chilled due to this. They then flew too low causing Africa to burn and turn into a desert. Zeus found out what was going on and took matters into his own hands. He killed Phaethon with a lightening bolt and his body fell into the Eridanos river.

His good friend Cygnus discovered what happened and plunged into the river in an attempt to save him. He did so repeated and his plunging action looked like that of a swan. Cygnus died trying to save his friend and as a reward Zeus placed him as a swan in the heavens.