Morgan le Fay (also Morgana, Morgaine, Morgan) was the antagonistic sorceress or fairy witch in the Arthurian legend.
Morgan le Fay was the daughter of King Gorlois (not Hoel) of Cornwall and Igraine. Most of the time, Morgan was identified as the half-sister of Arthur. Though Chretien de Troyes and some other authors just referred to her as the sister of Arthur. By the time of the Vulgate Cycle, Morgan was Arthur's half-sister, and the sister of Morgawse and Elaine.
According to modern writers, Morgan had a son named Mordred, by her own half-brother, Arthur, but most say that Mordred's mother was Arthur's other half-sister, named Morgawse, Morgan's younger sister.
It was possible that Gawain was also her son, according to The Perilous Cemetary. The tale doesn't mention Morgan by name, but it was written that Gawain's mother was a fairy. Morgan was usually said to be a fairy, as she was known as Morgan le Fay. However, most texts say that Gawain's mother was Morgawse, Morgan's younger sister.
Geoffrey of Monmouth mentioned Morgen as one of the nine sisters, living in Avalon (Vita Merlini, c. 1151). She made her first appearance here under the name Morgen. She was a healer, and had the extraordinary ability to fly and transform herself to resemble anyone or anything else. Arthur was brought to Avalon by Taliesin, where the king was healed by Morgan. Here, there was no indication of any relationship between Arthur and Morgan as siblings, except that she was his healer.
Some scholars at the time say that Avalon was situated on Glastonbury, an island in the middle of marshland. Gerald of Wales (who flourished in 12th century) believed the claims by monks of Glastonbury that Arthur was not taken there to Glastonbury/Avalon to be healed by Morgan, who was his cousin, but to be buried beside Guinevere.
In Chretien de Troyes' Erec and Enide, Morgan le Fay was a friend of Guingamar, lord of Avalon. Guingamar was one of the guests to the wedding of Erec and Enide. Later, in the story, Morgan was mentioned again as sister of Arthur and a great healer. Her name was mentioned again, in Knight of the Lion, where her ointment could even heal madness from Yvain.
However, in the Welsh romance, Gerient in the Mabinogion, which is basically the same story as Erec and Enide, Arthur does have a chief physician, named Morgan, who healed the hero, Gerient (Erec), but this Morgan Tud is clearly a man, with no blood relation to the king.
Later tales, say that Morgan was the wife of King Urien and mother of the hero Owain (Yvain). Though, early accounts such as by Geoffrey of Monmouth and Chretien de Troyes had never said anything about Yvain (Owain) being her son, and there was also no indication in either account that Morgan was married to Urien.
According to the Vulgate Merlin, Urien married Morgan shortly after Arthur received Excalibur from the Lady of the Lake. Their son was Yvain, the hero in Chretien's romance, Knight of the Lion. This Yvain should not be confused with another son of Urien, who was known as Yvain the Bastard. Also note that in Chretien's tale, there are no relation between Morgan and Yvain.
In the Welsh myth, before Geoffrey's time, Morgan was identified with the goddess Modron, the daughter of Welsh god Avallach, and the mother of Mabon. In the Welsh Triads, Modron was married to Urien, king of Rheged and mother of Owain (Yvain) and a duaghter named Morfudd. In the Arthhurian legend, Modron and Morgan le Fay became one and the same person, because they both were married to King Urien (brother of King Lot), and both were mother of the hero Owain (Yvain). It is most likely that Modron was changed into Morgan when the legend arrived in Brittany.
Morgan was also identified with another Breton goddess, Dahut or Ahes, the princess, who had caused the destruction of her city Ys. Dahut/Ahes was originally a Breton sea goddess, though later accounts say that she had died when the sea had flooded Ys, or that she had being transformed into a mermaid. However, in Brittany and elsewhere Morgan was usually a male name.
In the early legend, Morgan's role was benevolent who used her power for healing. She was the fairy queen or one of the queens of Avalon. She was said to have learned her magic from Merlin. Malory says that Morgan learned magic when she was in a nunnery (Le Morte d'Arthur, Book I chapter 2).
There are similarities of Morgan with the great Irish goddess, Morrigan. Most of the time Morgan appeared as a beautiful young woman, sometimes as an old hag, like in Gawain and the Green Knight, c. 1350. Morrigan also had the same ability to shape-shift between young and old, beautiful and ugly. Like Morrigan, she was able to transform herself to look like any animal or inanimate objects.
Morgan le Fay was responsible for Gawain's adventure of the beheading games with the Green Knight. Morgan had given the Green Knight the ability to survive after having had his head severed. Morgan had hoped that this event would frighten Guinevere to death.
By the time of the Vulgate Cycle and Prose Tristan, her character began to change, where she became one of mortal enemies of Arthur and Guinevere. Her role became more sinister; later writers tend to portray her as a wicked and maligned character.
Her hatred for Guinevere may have stemmed from one story, when she was serving as the queen's lady-in-waiting. She was in love with a young knight, who happened to be the queen's cousin. Morgan and the knight were lovers until Guinevere heard of her trysts, so the queen broke up their relationship, in case they cause a scandal. Morgan never forgave Guinevere this incident and she sought revenge upon the queen. After this Morgan went in search for Merlin, learning magic, in exchange for offering her love to the sorcerer.
In the Vulgate Lancelot and Malory's Morte d'Arthur, she had fallen in love with Lancelot, whom she encountered several times. Several times she had imprisoned Lancelot refusing to release him until the hero became her lover. Each time he had refused. One time, she had spirited Lancelot away with two other queens, who were also powerful sorceresses (in Malory's version, four queens had abducted Lancelot). According to Malory, when Arthur was dying, Morgan and three other ladies, Queen of the Northgales and Queen of the Wasteland and Nimue (Niniane) arrived in a black ship. Morgan intends to take Arthur to Avalon, where she could heal her brother's wounds. The Vulgate Mort Artu only mentioned Morgan and unspecific number of ladies on the ship.
Geoffrey and Wace mentioned Arthur went to Avalon to be healed, but no mention of Morgan or ship. Layamon wrote of Arthur going to a boat, but no Morgan, but he did say that Argante, the fairy queen of Avalon, would heal the dying king's wounds. Layamon described Argante as a very radiant elf. Whether Morgan and Argante were one and the same person, is not very clear.