The Green Knight is a Danish fairy tale, collected by Svend Grundtvig (1824-1883) in Danish Fairy Tales (18??) and by Evald Tang Kristensen (1843-1929) in Eventyr fra Jylland (1881).Andrew Lang included a translation of Kristensen's version in The Olive Fairy Book (1907).
This tale combines Aarne-Thompson type 510A with type 425N, the bird husband, and type 432, the prince as bird. Others of the first type include Cinderella, The Sharp Grey Sheep, The Golden Slipper, The Story of Tam and Cam, Rushen Coatie, Fair, Brown and Trembling and Katie Woodencloak; of the second two, The Feather of Finist the Falcon, The Blue Bird, and The Greenish Bird.
A queen dying of cancer asked her husband to do whatever their daughter asked of him, and the king promised. The widow of a count and her daughter did everything to make themselves the princess's favorites (in some variants persuading the princess to have them stay at the castle), and then the widow told her that they could not stay unless the king married her. The princess implored the king to do it, and when his objections could not convince her, he married the woman.
As soon as she was her stepmother, the woman began to maltreat the princess. The king, seeing this, sent the princess to a summer palace, or had one built for her. He went there one day to bid her farewell because he was going on a long journey, to a great tournament. She told him to greet her to the Green Knight. At the tournament, he met no Green Knight, but on the way home, he came through a forest where he found a swineherd, and on asking whose pigs they were, was told they were the Green Knight's. He went on and found the marvellous castle where the Green Knight, a handsome young man lived. He gave him his daughter's greetings. The Green Knight had never heard of her—in some variants, he says she must have been thinking of the green of the graveyard—but makes the king welcome and gives him a gift: either a green book or a casket with his portrait.