Although he flew like the wind the Gorgon sisters would have overtaken him if he had been plain to their eyes. But the dogskin cap of Hades saved him, for the Gorgon sisters did not know whether he was above or below them, behind or before them. On Perseus went, flying toward where Atlas stood. He flew over this place, over Libya. Drops of blood from Medusa's head fell down upon the desert. They were changed and became the deadly serpents that are on these sands and around these rocks. On and on Perseus flew toward Atlas and toward the hidden valley where the nymphs who were again to guard the magic treasures had their dwelling place. But before he came to the nymphs Perseus had another adventure. In Ethopia, which is at the other side of Libya, there ruled a king whose name was Cepheus. This king had permitted his queen to boast that she was more beautiful than the nymphs of the sea. In punishment for the queen's impiety and for the king's folly Poseidon sent a monster out of the sea to waste that country. Every year the monster came, destroying more and more of the country of Ethopia. Then the king asked of an oracle what he should do to save his land and his people. The oracle spoke of a dreadful thing that he would have to do--he would have to sacrifice his daughter, the beautiful Princess Andromeda. The king was forced by his savage people to take the maiden Andromeda and chain her to a rock on the seashore, leaving her there for the monster to devour her, satisfying himself with that prey. Perseus, flying near, heard the maiden's laments. He saw her lovely body bound with chains to the rock. He came near her, taking the cap of darkness off his head. She saw him, and she bent her head in shame, for she thought that he would think that it was for some dreadful fault of her own that she had been left chained in that place. Her father had stayed near. Perseus saw him, and called to him, and bade him tell why the maiden was chained to the rock. The king told Perseus of the sacrifice that he had been forced to make. Then Perseus came near the maiden, and he saw how she looked at him with pleading eyes. Then Perseus made her father promise that he would give Andromeda to him for his wife if he should slay the sea monster. Gladly Cepheus promised this. Then Perseus once again drew his sickle-sword; by the rock to which Andromeda was still chained he waited for sight of the sea monster.