The Three Daughters of King O'Hara

In the late 19th century, Alfred Nutt described the story as a "Beauty and the Beast tale",[3] another type of the ATU index related to the animal bridegroom tales. Similarly, in the early 20th century, Norwegian folklorist Reidar Thoralf Christiansen classified the tale as belonging to type 425, "The Search for the Lost Husband", of the international Aarne-Thompson-Uther Index.[4]

More specifically, the tale is classified in the international Aarne-Thompson-Uther Index as type ATU 425A, "The Animal as Bridegroom". in this tale type, the heroine is a human maiden who marries a prince that is cursed to become an animal of some sort. She betrays his trust and he disappears, prompting a quest for him.[5] For example, the hero of the tale was said to be transformed into a white dog by the druidecht of the Queen of Tir-na-Nog.[6]

The tale also contains type ATU 302, "The Ogre's (Devil's) Heart in the Egg",[7] a set of stories where the villain hides its heart or soul in an external place and can only be defeated if the heroes destroy its external location.

According to Hans-Jörg Uther, the main feature of tale type ATU 425A is "bribing the false bride for three nights with the husband".[8] In fact, when he developed his revision of Aarne-Thompson's system, Uther remarked that an "essential" trait of the tale type ATU 425A was the "wife's quest and gifts" and "nights bought".[9]

According to Jan-Öjvind Swahn's study on some 1,100 variants of Cupid and Psyche and related types, the motif of the "wishing chair" appears in Celtic, Irish and British variants.[10] In the same study, he concluded that the dog as the animal husband appears "confined to the Germanic and Celtic areas".[11]

The motif of the separation of the heroine from her children is located by scholarship across Celtic and Germanic speaking areas.[12][13][14]

In a variant from County Mayo, collected from a sixty-year-old woman named Una Canavan with the title The Hill of Needles, a widowed nobleman has three daughters. One day, he forgets to lock up a certain door of his house, and his eldest daughter enters it. She talks to the chair that she wants to marry an officer. She tells her middle sister, who wishes to the chair for a husband. The third also wishes to the chair, which says a white fawn shall marry her. The promised husbands appear to the ladies, including the white fawn. The lady learns the fawn is a man, who asks her which form she prefers; she answers that he should be a man at night and a fawn by day. She wants to visit her family, but her husband warns her that if she sheds a tear, a coach will not return for her to bring her home to the fawn husband. She goes to her father's house and gives birth to a son, who is taken from her. The next year, she gives birth to a daughter, who is also taken from her. She sheds a tear and the coach does not come. The lady returns to the husband's home on foot and finds only a field of nettles. She sees another coach with her husband inside and follows it; along the road, three houses that she visits, each housing one of her husband's sisters and one of her children. Her sisters-in-law give her scissors, a tablecloth and a comb. Her husband bids her goodbye, since his coach will traverse the Hill of Big Needles and the Hill of Little Needles, reachable only by iron shoes. She throws some blood on her husband's shirt as he departs, and looks for a blacksmith to create on the iron shoes. She reaches the other side, finds a woman crying about the man's shirt with blood and washes it. The lady buys three nights with her husband from the new wife and learns from him that his new wife can inly be killed by finding an egg inside a duck, inside a ram, inside a well, and throw it at her mole.[15]

Scottish folklorist John Francis Campbell claimed that an oral version told in 1812 to a man named John Dewar by a servant woman, was a version of a "popular tale" written in Wales "about 400 years ago".[16] In this tale, titled an t urisgeal aig na righre Righ na thuirabhinn agus righ nan Ailp, the King of Ailp and his kingdom were killed by the druids, leaving only a son and a daughter. His daughter was trained by the druids and gained skin green as moss. The son climbs a mountain name Bean ghloine with his father's sword and scepter. Another druid curses him into animal form (a greyhound). He abandons the items on the mountain and flees to his sister. The prince, then, must remain as a greyhound until a maiden agrees to marry him, and his sister nurses three children and receives a kiss from a king's son. Some time later, the King of the Urbhin, while at war with another king, loses his way into a thick mist and ends up at the greyhound's castle. He kicks up the former king's bones and the greyhound, for this affront, demands the king of Urbhin surrenders one of his daughters as ransom. The king surrenders his daughter and she marries the greyhound. The princess lives with the greyhound and discovers he is a human prince. They marry, and her sisters become jealous. The princess's brother also falls in love with the greyhound's sister, the green girl, after drinking a potion of "mheadair Bhuidh" (yellow mead) from her hand. The princess's sisters conspire with a druid to dethrone her sister and become the greyhound's queen: when the time comes to give birth, for three times the princess's child is taken from her by a green hand in a window, but each child cries and the mother takes the teardrops. The greyhound, now a human prince, announces he will marry the one who can retrieve his father's sword and scepter from the glass mountain. The princess accomplishes it, but her sisters take the credit. Next, they must wash the bloodstained shirts that belonged to those slain by the druids. The princess also washes all but one, and stays three nights on the (now human) greyhound's bed. On the first two nights, he is asleep, but acknowledges his wife on the third night, and they return to the former kingdom of Ailp with the green girl (his sister). The tale continues as the "wicked druid" Dubhmalurraidh changes one of the princess's sisters into her shape, to cast the king into confusion. However, the green sister produces her father's sword and scepter (retrieved by her sister-in-law) and her three nephews.[17]

Adeline Ritterhaus summarized another Icelandic variant she named Der zum Riesen verzauberte Königssohn ("The King's Son changed into a Giant"). In this tale, a royal couple has three daughters. One day, the king gets lost in a thick mist, until a giant appears with a proposition: he will save the king's life, in exchange for the king's third daughter. After three times, the king concedes and agrees. He returns home and explains the story to his daughters. The youngest daughter marries the giant. The princess gives birth to three children, two boys and a girl, which are taken from her by a giantess and a red-brown she-dog. At the end of the tale, the giant is disenchanted into his true form, Prince Sigurdur, who reveals that the giantess was his mother and the she-dog his sister, now both restored to their original forms.[18]

In a variant from Letcher County, Kentucky collected by Marie Campbell with the title The Girl That Married a Flop-Eared Hound, a widowed king walks in the wood and sees a "fine hound-dog with long flop-ears". He asks the dog what it is doing there and the dog, to the king's surprise, answers that it wants to marry one of the king's daughters. Only the youngest daughter accepts the proposal, with the condition that she can visit her famlily whenever she wants. On their wedding day, the sisters use blindfolds to bear the humiliation of having a dog as brother-in-law, but instead a fine young man appears to marry their sister. One day, the princess is pregnant and wishes to give birth under her father's roof. The dog husband agrees, as long as she never reveals her husband's name. On two occasions, she gives birth to her child (the first a boy, the second a girl), who disappears two days after their birth when "fairy music" plays, leaving only wine and cookies on the cradle. The princess's sisters accuse the dog husband, and insist she reveals his name, but she remains steadfast. On the third visit, however, the princess gives birth to her third child and reveals her husband's name, "Sunshine on the Dew". This time, the child disappears, and so does her husband. She then goes on a quest for him, meeting three old women on the journey who give her a pair of scissors, a thimble and a needle. The princess uses the magical objects as bargaining chips to be able to spend a night with her husband, who is to be married to another woman.[19] The tale was also classified as ATU 425A, "The Animal as Bridegroom".[20]