Melusine
In European mythology, the Melusine or Melusina is represented as a mermaid with two tails. Unlike the marine mermaid, the melusine is a spirit of fresh waters, in sacred springs and rivers. She figures as a heraldic charge, above all in German and Scandinavian coats-of-arms, where she supports one scaly tail in each arm. She may appear crowned. The Coat of Arms of Warsaw features a melusina (identified in Polish as a syrenka; compare Greek siren), brandishing a sword and shield. She is the water-spirit from the Vistula who identified the proper site for the city to Boreslaus of Masovia in the late 13th century.
The melusine myths are connected with the northern, most Celtic areas of Gaul and the Low Countries. When Count Siegfried of the Ardennes bought the feudal rights to Luxembourg in 963 CE, his name became connected with the local melusine.
The melusine is one of the pre-Christian water-faeries who were sometimes responsible for changelings. The "Lady of the Lake," who spirited away the infant Lancelot and raised the child, was such a water nymph.
A version of a Melusine tale, by Jean d'Arras, compiled about 1382 - 1394 and worked into a collection of "spinning yarns" told by ladies at their spinning was translated into English about 1500, and often printed in the 15th and 16th century. (There is also a prose version called the Chronique de la princesse.) It tells how Elynas, the King of Albany (a poetical euphemism for Scotland) went hunting one day and came across a beautiful lady in the forest. She was Melusine's mother, Pressyne. He persuaded her to marry him but she agreed, only on the condition— for there is often a hard and fatal condition attached to ant pairing of fay and mortal— that he must not enter her chamber when she birthed or bathed her children.
She gave birth to triplets. When he violated this taboo, Pressyne left the kingdom, together with her three daughters, and traveled to the lost Isle of Avalon.
The three girls, Melusine, Melior, and Palatyne grew up in Avalon. On their fifteenth birthday, Melusine, the eldest, asked why they had been taken to Avalon. Upon hearing of their father's broken promise, Melusine sought revenge. She and her sisters captured Elynas and locked him, with his riches, in a mountain. Pressyne became enraged when she learned what the girls had done, and punished them for their disrespect to their father. Melusine was condemned to take the form of a serpent from the waist down every Saturday.
Raymond of Poitou came across Melusine in a forest in France, and proposed marriage. Just as her mother had done, she laid a condition, that he must never enter her chamber on a Saturday. He broke the promise and saw her in the form of a part-woman part-serpent. She forgave him. Only when, during a disagreement with her, he called her a "serpent" in front of his court, did she assume the form of a dragon, provide him with two magic rings and fly off, never to return.
For other European water sprites dangerous to humans, especially men, see Lorelei, Nixie.
"Melusina" would seem to be an uneasy name for a girl-child in these areas of Europe, but the Duchess of Kendal, George I of England's German mistress, was christened Ehrengard Melusina von der Schulenburg in 1667.
