I was reading the White Queen by Philippa Gregory about the War of the Roses. It's told from the viewpoint of Elizabeth Woodeville, the mother of the princes in the tower. She believes herself to be descended from Melusina a water goddess that is half fish and half woman. In many of the images of Melusina, she is portrayed as having two leg-like tails. A wandering knight found her in the forest by a fountain and fell in love with her. She agreed to marry him and bore him children. But when he found out she still reverted to fish form she disappeared with their daughters and he never saw her again.
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