Here is a story of one of these heroes.  His mother was the daughter of an Argive king, and was named Danaë.  He was named Perseus, and had bright eyes and golden hair like the morning.  When he was a little babe, he and his mother were out at sea, and were cast on the isle of Seriphos, where a fisherman named Dictys took care of them.  A cruel tyrant named Polydectes wanted Danaë to be his wife, and, as she would not consent, he shut her up in prison, saying that she should never come out till her son Perseus had brought him the head of the Gorgon Medusa, thinking he must be lost by the way.  For the Gorgons were three terrible sisters, who lived in the far west beyond the setting sun.  Two of them were immortal, and had dragon’s wings and brazen claws and serpent hair, but their sister Medusa was mortal, and so beautiful in the face that she had boasted of being fairer than Pallas.  To punish her presumption, her hair was turned to serpents, and whosoever looked on her face, sad and lovely as it was, would instantly be turned into stone.