There was Cassiopaeia, queen of Aethiopia, who boasted that her beauty outshone the beauty of all the sea-nymphs, so that in anger they sent a horrible sea-serpent to ravage the coast. The king prayed of an Oracle to know how the monster might be appeased, and learned that he must offer up his own daughter, Andromeda. The maiden was therefore chained to a rock by the sea-side, and left to her fate. But who should come to rescue her but a certain young hero, Perseus, who was hastening homeward after a perilous adventure with the snaky-haired Gorgons. Filled with pity at the story of Andromeda, he waited for the dragon, met and slew him, and set the maiden free. As for the boastful queen, the gods forgave her, and at her death she was set among the stars. That story ended well. But there was once a queen of Thebes, Niobe, fortunate above all women, and yet arrogant in the face of the gods. Very beautiful she was, and nobly born, but above all things she boasted of her children, for she had seven sons and seven daughters. Now there came the day when the people were wont to celebrate the feast of Latona, mother of Apollo and Diana; and Niobe, as she stood looking upon the worshippers on their way to the temple, was filled with overweening pride. "Why do you worship Latona before me?" she cried out. "What does she possess that I have not in greater abundance? She has but two children, while I have seven sons and as many daughters. Nay, if she robbed me out of envy, I should still be rich. Go back to your houses; you have not eyes to know the rightful goddess." Such impiety was enough to frighten any one, and her subjects returned to their daily work, awestruck and silent. But Apollo and Diana were filled with wrath at this insult to their divine mother. Not only was she a great goddess and a power in the heavens, but during her life on earth she had suffered many hardships for their sake. The serpent Python had been sent to torment her; and, driven from land to land, under an evil spell, beset with dangers, she had found no resting-place but the island of Delos, held sacred ever after to her and her children. Once she had even been refused water by some churlish peasants, who could not believe in a goddess if she appeared in humble guise and travel-worn. But these men were all changed into frogs.