"The Swan Maiden" is a very widespread folktale common to mainland Europe, Russia and even Eastern Asia. Sometimes it overlaps with Aarne-Thompson 400 "The Quest for the Lost Wife".
The tale broadly goes like this: the swan maidens (occasionally men too) are creatures who shapeshift from human form to -usually- swan form thanks to a bird skin or some sort of feathered dress. Often a man happens upon several maidens bathing in a lake or pool, and after spying on them, he steals one dress -which prevents the maiden from leaving, or somehow renders her helpless- and forces her to marry him.
Sometimes, the husband must find his missing wife or undo a curse which she has been placed under.
The Brothers Grimm collected a German version (""The Drummer"), and Joseph Jacobs made his own version based on several European tales ("The Swan Maidens": here and here), but the myth is very widespread. Some different versions can be found in the next links: here, here and here.
- Adaptational Nice Guy: In most versions, a man spies on the bathing maidens, and outright steals the most beautiful one's dress to force her into marriage. In "The Drummer", the male lead simply picks an apparently abandoned dress that he finds lying on the ground by the lakeside, he willingly hands it over when its owner appears to demand her property back, and he asks the woman if he can help her out.
- The maidens can usually transform into some species of waterfowl like swans or ducks.
- In Pakistani tale "Prince Bairâm and the Fairy Bride", Safeyd, the king of the giants from the mountains of Kôh Kâf, can turn into a snow-white horse.
- Captain Obvious: At the end of "The Three Swans", the narrator says, "they all lived together in peace and happiness, and if they have not died, then they must be still alive".
- Clothes Make the Superman: In Japanese versions, the feather garment of a celestial maiden (tennyo) grants her the power of flight. A man or an elderly couple hides her feather garment away to keep them company on earth.
- Don't Go in the Woods: In "The Drummer", the woods surrounding the glass mountain are home to dangerous man-eating giants.
- Giant Equals Invincible: Averted in "The Drummer", when the titular character bluffs a giant by pointing out he can be killed by average-sized humans when he is sleeping.
- Girl in the Tower: In "Prince Bairâm and the Fairy Bride", Ghulâb Bâno's parents lock her away in a tower of one hundred iron doors to prevent her from returning to her lover.
- God in Human Form: In Japanese tale "The Feathery Robe", the owner of the winged dress is a goddess resembling a human woman.
- Gone Swimming, Clothes Stolen: The tale involves a human witness a group of cranes, swans, seals, porpoises, or other animals "undress" from their skins and turn into beautiful women bathing in a pond. The human will steal the skin of one of the women and only agree to give it back should she agree to marry him. Occasionally, the women are from the celestial realm and the human steals actual clothes rather than skin.
- Happily Ever After: Played straight in versions where the maiden falls in love with the man who found her garment. Averted in Swedish tale "The Swan Maiden", where the maiden flies away as soon as she gets her dress back, even though she had been married to the huntsman seven years by that point.
- Impossible Task: In "The Drummer", the character must empty out one large lake with one thimble, and then lay all the fishes side by side, and according to their kind and size, before the nightfall; the next day, he must cut down a whole forest, split the wood into logs, and pile them up, and he must be done by the evening. In the third day, he must arrange all the wood in one heap and burn it.
- Interspecies Adoption: In at least one Japanese version, the celestial maiden (tennyo) becomes the daughter of an elderly couple when they hide her feather garment.
- Kill It with Fire: In "The Drummer", the lead character throws the old witch into a bonfire to save the three maidens.
- Love at First Sight: In "Prince Bairâm and the Fairy Bride", the fairy Ghulâb Bâno falls for Bairâm as soon as she sees him.She then looked towards the steps and saw the prince. At once her heart escaped from her body, and she fell in love with him.
- Nameless Narrative: Often the characters go by nicknames or mere descriptors.
- Our Dragons Are Different: "The Three Swans" features three dragons which can transform into giant snakes or fire-breathing turtles.
- Our Giants Are Bigger: In "The Drummer", the giants inhabiting the wood surrounding the glass mountain are man-eaters, but fortunately they are not too bright.
- Reptiles Are Abhorrent: In "The Three Swans", the huntsman must endure the torture of three dragons for three days to remove his wife's. Every time they turn into large snakes or fire-breathing turtles.
- Rule of Seven: In the Swedish "The Swan Maiden", the huntsman and the maiden remain married for seven years until the maiden gets her dress back and flies away.
- Rule of Three:
- In "The Drummer", the main character is led to the glass mountain by three giants. After climbing up the mountain, he knocks on the witch's door three times before the woman opens the door. And he must fulfill three impossible tasks imposed by the witch in order to free the king's daughters.
- In "The Nine Peahens and the Golden Apples", the king has three sons, and the male lead spends three days taking care of the witch's mare.
- "The Three Swans" has the titular three birds. Also, the hunter must endure the torture of three dragons for three days to undo the swans' curse.
- Shapeshifting Lover: The maiden usually falls in love with the male lead.
- Solitary Sorceress: In "The Drummer", an old witch lives alone on top of the glass mountain.
- Superhuman Trafficking: Many versions of the tale involve unscrupulous men forcing a maiden into marriage after stealing her animal skin, trapping her in human form.
- Swans A-Swimming: The women are normally swans, but they leave their feathered cloaks behind when they bathe as humans.
- What Measure Is a Humanoid?: Generally, the stories involve romance between a human male and a shape-shifting female spirit.