Perseus then resumed his travels. His winged sandals bore him over deserts and mountains, until he arrived at Æthiopia, the kingdom of King Cepheus. Here he found the country inundated with disastrous floods, towns and villages destroyed, and everywhere signs of desolation and ruin. On a projecting cliff close to the shore he beheld a lovely maiden chained to a rock. This was Andromeda, the king's daughter. Her mother Cassiopea, having boasted that her beauty surpassed that of the Nereides, the angry sea-nymphs appealed to Poseidon to avenge their wrongs, whereupon the sea-god devastated the country with a terrible inundation, which brought with it a huge monster who devoured all that came in his way.
In their distress the unfortunate Æthiopians applied to the oracle of Jupiter-Ammon, in the Libyan desert,
and obtained the response, that only by the sacrifice of the king's daughter to the monster could the country and people be saved.
Cepheus, who was tenderly attached to his child, at first refused to listen to this dreadful proposal; but overcome at length by the prayers and solicitations of his unhappy subjects, the heart-broken father gave up his child for the welfare of his country. Andromeda was accordingly chained to a rock on the sea-shore to serve as a prey to the monster, whilst her unhappy parents bewailed her sad fate on the beach below.
On being informed of the meaning of this tragic scene, Perseus proposed to Cepheus to slay the dragon, on condition that the lovely victim should become his bride. Overjoyed at the prospect of Andromeda's release, the king gladly acceded to the stipulation, and Perseus hastened to the rock, to breathe words of hope and comfort to the trembling maiden. Then assuming once more the helmet of Aïdes, he mounted into the air, and awaited the approach of the monster.
Presently the sea opened, and the shark's head of the gigantic beast of the deep raised itself above the waves. Lashing his tail furiously from side to side, he leaped forward to seize his victim; but the gallant hero, watching his opportunity, suddenly darted down, and producing the head of the Medusa from his wallet, held it before the eyes of the dragon, whose hideous body became gradually transformed into a huge black rock, which remained for ever a silent witness of the miraculous deliverance of Andromeda. Perseus then led the maiden to her now happy parents, who, anxious to evince their gratitude to her deliverer ordered immediate preparations to be made for the nuptial feast. But the young hero was not to bear away his lovely bride uncontested; for in the midst of the banquet, Phineus, the king's brother, to whom Andromeda had previously been betrothed, returned to claim his bride. Followed by a band of armed warriors he forced his way into the hall, and a desperate encounter took place between the rivals,
which might have terminated fatally for Perseus, had he not suddenly bethought himself of the Medusa's head. Calling to his friends to avert their faces, he drew it from his wallet, and held it before Phineus and his formidable body-guard, whereupon they all stiffened into stone.
Perseus now took leave of the Æthiopian king, and, accompanied by his beautiful bride, returned to Seriphus, where a joyful meeting took place between Danaë and her son. He then sent a messenger to his grandfather, informing him that he intended returning to Argos; but Acrisius, fearing the fulfilment of the oracular prediction, fled for protection to his friend Teutemias, king of Larissa. Anxious to induce the aged monarch to return to Argos, Perseus followed him thither. But here a strange fatality occurred. Whilst taking part in some funereal games, celebrated in honour of the king's father, Perseus, by an unfortunate throw of the discus, accidentally struck his grandfather, and thereby was the innocent cause of his death.
After celebrating the funereal rites of Acrisius with due solemnity, Perseus returned to Argos; but feeling loath to occupy the throne of one whose death he had caused, he exchanged kingdoms with Megapenthes, king of Tiryns, and in course of time founded the cities of Mycenæ and Midea.