The Mists of Avalon is a 1983 historical fantasy novel by American writer Marion Zimmer Bradley, in which the author relates the Arthurian legends from the perspective of the female characters. The book follows the trajectory of Morgaine (Morgan le Fay), a priestess fighting to save her Celtic religion in a country where Christianity threatens to destroy the pagan way of life. The epic is focused on the lives of Morgaine, Gwenhwyfar (Guinevere), Viviane, Morgause, Igraine and other women of the Arthurian legend.

The Mists of Avalon is in stark contrast to most other retellings of the Arthurian tales, which consistently cast Morgan le Fay as a distant, one-dimensional evil sorceress, with little or no explanation given for her antagonism to the Round Table. In this case, Morgaine is presented as a woman with unique gifts and responsibilities at a time of enormous political and spiritual upheaval who is called upon to defend her indigenous heritage against impossible odds.

The story is told in four large parts: "Book One: Mistress of Magic"; "Book Two: The High Queen"; "Book Three: The King Stag"; and "Book Four: The Prisoner in the Oak". The novel was a best-seller upon its publication and remains popular to this day. Bradley and Diana L. Paxson later expanded the book into the Avalon series.

Plot Igraine, younger half-sister of Vivian and older sister to Morgause, is married at fifteen to the much older Duke Gorlois of Cornwall and gives birth to Morgaine. Igraine later marries king Uther Pendragon after Gorlois dies in battle against Uther. Before Igraine knew of Gorlois's death, Uther consulted with Merlin, who used magic to make Uther appear as Gorlois and thus gained access to Igraine at Tintagel, conceiving Arthur. Morgaine witnesses Uther's accession to Caerleon's throne after his predecessor, Ambrosius, dies of old age.

When Morgaine is eleven years old and Arthur six, there is an attempt to murder Arthur. Their aunt, the high priestess Viviane, arrives in Caerleon and advises Uther to have Arthur fostered far away from the court for his own safety. Uther agrees, and also allows Viviane to take Morgaine to Avalon, where she is trained as a priestess of the Mother Goddess. During this period, Morgaine becomes aware of the rising tension between the old Pagan and the new Christian religions. After seven years of training, Morgaine is initiated as a priestess of the Mother, and Viviane begins priming her as the next Lady of Avalon.

When Vivian's son Lancelet visits Avalon, Morgaine falls in love with him, but her happiness is cut short when they discover Gwenhwyfar lost in the mist and Lancelet is smitten with her beauty.

Months after her initiation, Morgaine is given in a fertility rite to the future High King of Britain. Their union is not meant to be personal, but rather a symbolic wedding between the king and the land he is to defend. They engage in ritual sex, each unknowing of the other's actual identity. The following morning they talk and, after recognizing each other as Morgaine and Arthur, are horrified to realize what they have done. Two months later, Morgaine is devastated to find that she is pregnant.

After Uther dies fighting the Saxon invaders, Arthur claims the throne of Britain despite rumors about whether his father was Gorlois or Uther. Arthur must now defend Britain against the Saxons; Viviane gives him the sacred sword Excalibur and has Morgaine make him an enchanted scabbard that will prevent him from losing blood. With the combined forces of Avalon and Caerleon, Arthur repels the invaders, brings peace to the land, and marries Gwenhwyfar.

As Morgaine's unborn child grows within her, so do her feelings of anger and betrayal toward Viviane, whom she believes tricked her into bearing a child to Arthur for her own purposes. After considering abortion and briefly wandering into the realm of the fairies, she leaves Avalon for the court of her aunt Morgause, Queen of Lothian, where she gives birth to her son, naming him Gwydion. Morgause, spurred by her own and her husband Lot's ambition, tricks Morgaine into allowing her to rear Gwydion. Morgause uses magic to learn who his father is but promises secrecy to Morgaine. To escape Lot's unwanted advances, Morgaine leaves Lothian and returns to Arthur's court as a lady-in-waiting to Queen Gwenhwyfar. Morgaine does not see her son again until he is grown and a druid priest of Avalon.

When Gwenhwyfar fails to produce an heir, she is convinced that God is punishing her for her sins. She considers her greatest sins to be her failure to persuade Arthur to outlaw pagan religious practice in Britain and her forbidden love for Galahad, Arthur's cousin and finest knight, also known as Lancelet. Although Lancelet reciprocates Gwenhwyfar's love, he is also Arthur's closest friend and an honorable man. This situation causes suffering to both Lancelet and Gwenhwyfar.

On the eve of a decisive battle against the Saxons, Gwenhwyfar prevails upon Arthur to put aside Uther's Pendragon banner and replace it with her own Christian banner. As her religious fanaticism grows, relations between Avalon and Caerleon grow strained. Still, in her desperation over her failure to carry a child to term, Gwenhwyfar asks Morgaine for help, threatening to have an extramarital affair so she can become pregnant. In an attempt to keep Gwenhwyfar from doing so, Morgaine reveals to Gwenhwyfar that Arthur already has a son, though he does not know it; not telling her that she is the mother. Later, Arthur asks Lancelet to join him and his wife in his bed to conceive a child, and to satisfy the suffering of both Gwenhwyfar and Lancelet, stating that the child would be conceived on his bed and raised as his own. Lancelet at first refuses, but is finally convinced; however, no child is conceived even from this.

After the battle, Arthur moves his court to Camelot, which is more easily defended than Caerleon. Seeking to free both Lancelet and Gwenhwyfar from the forbidden love that traps them both, Morgaine tricks Lancelet into marrying Gwenhwyfar's cousin, Elaine, angering Gwenhwyfar. Later, during a dispute with Arthur over their lack of an heir, Gwenhwyfar breaks Morgaine's confidence and tells Arthur of Gwydion, then realizes Morgaine is his mother and Gwydion the child of incest. Arthur summons Morgaine and orders her to tell the truth, and she obeys. Gwenhwyfar, now believing that the lack of a royal heir is God's punishment for Arthur's union, however unwitting, with his half-sister Morgaine, urges Arthur to confess the encounter to the bishop, who imposes strict penance upon him. Then she and Arthur arrange for Morgaine to marry into Wales, far from Camelot. But because of a misunderstanding, Morgaine, who thought she would be marrying the king's younger son Accolon, a druid priest of Avalon and warrior, finds herself betrothed to King Uriens of North Wales, who is old enough to be her grandfather.

Arthur yearns to meet Gwydion and perhaps foster him at Camelot, but each time he brings up the subject with Gwenhwyfar she refuses to discuss it. Meanwhile, Gwydion is taken by Viviane to Avalon.

Morgaine marries Uriens and moves to North Wales as its queen, and enjoys a good relationship with Uriens and his youngest son, Uwaine, whom she grows to think of as her own son. Years later, she begins an affair with her step-son Accolon. The "little people" of the hills, who keep to the old pagan ways, regard Accolon and Morgaine as their spiritual king and queen. Uriens suspects nothing, but Accolon's older brother Avalloch does become suspicious; he eventually tries to blackmail Morgaine into sleeping with him as well. Morgaine sends Avalloch out on a boar hunt and he is killed by the boar, apparently through Morgaine's magic.

Gwydion, now grown, goes to the Saxon courts to learn warfare far from Arthur's eye. Impressed by his cleverness, the Saxons name him Mordred ("Evil Counsel"). Years later, at a Pentecost feast at Camelot, he introduces himself as Queen Morgaine's son and Queen Morgause's foster son, though he calls Queen Morgause "Mother" and Morgaine by her name. Because of his resemblance to his older relative, Lancelet, he must often tell people that Lancelet is not his father, but cannot say who his father is due to the shame of incest. To earn his knighthood with no suspicion of preferential treatment, Gwydion challenges Lancelet to single combat during a tourney and they fight. Gwenhwyfar, who has warmed to Gwydion, protests and Arthur interrupts the match. Lancelet makes Gwydion a knight of the Round Table, naming him Mordred.

Morgaine tells Accolon, who is now Uriens's heir, of the sacred marriage she made with Arthur years before. She convinces him that they must take the kingdom back from Arthur and the Christians and bring it back under the sway of Avalon. Morgaine discovers she is pregnant and is not sure if the child is Uriens' or Accolon's, but has an abortion because she is too old to give birth safely. The attempted coup fails and Arthur kills Accolon in single combat, sending a warning to Morgaine. As Uriens recovers from the shock of losing a second son and his wife's betrayal, Morgaine leaves Wales forever and returns to Avalon.

Years later, the Sacred Regalia of Avalon, a spear, a dish, and a cup, are stolen and presented to the Christian church in Camelot as an offering. Morgaine returns to Camelot with the priestess Raven during the Pentecost festival disguised as peasants. At the start of the holy rites, enraged and wielding great magic, Morgaine invokes the Great Mother Goddess to retrieve the regalia. The assembled court sees the manifestation of this magic as the revelation of the Holy Grail, which disappears as Raven collapses and dies.

When the knights of the Round Table leave to search for the Holy Grail, which drives Lancelet insane and results in the deaths of others, Mordred attempts to usurp the throne. The armies of Arthur and Mordred eventually fight but in the end, Mordred dies and Arthur is mortally wounded, Morgaine having earlier taken the magical scabbard. Morgaine takes the dying Arthur through the mists to Avalon, reassuring him that he did not fail in his attempt to save Britain from the approaching dark times. Arthur dies as the shoreline comes into view. Morgaine buries him in Avalon and remains there to tell the tale of Camelot.

Characters Morgaine — Narrator, protagonist. Her character is capable of second sight (a gift of her Goddess) and transfiguration. She is the daughter of Gorlois and Igraine and the half-sister of Arthur. She is of notable status in the eyes of the old tribes of Britain and the post Roman aristocracy, being both High Priestess of Avalon and Duchess of Cornwall in her own right. Portrayed as a tragic character, Morgaine is torn between her loyalty to Avalon and her unfulfilled love for Lancelet, although she has other lovers in the book, notably Arthur, Kevin, and Accolon. Like Arthur, she is extremely charismatic. She often considers herself the victim of fate, having no choice in the decisions she makes in life. She is doomed to witness the demise of the old ways of Avalon, but in the end makes peace with certain aspects of Christianity, as she sees that she never fought the religion itself, but rather the narrow-minded views of some of its priests. She concludes that some memory of the ancient beliefs of Britain will live on, feeling that the Goddess she worshipped did not die with the coming of Christianity: rather, the Goddess just took another form in the image of the Virgin Mary.