Once upon a time there were two princes who were twins. Their names were Acrisius and Pr tus, and they lived in the pleasant vale of Argos, far away in Hellas. They had fruitful meadows and vineyards, sheep and oxen, great herds of horses feeding down in Lerna Fen, and all that men could need to make them blest: and yet they were wretched, because they were jealous of each other."