Guinevere was the legendary queen consort of King Arthur. She was most famous for her love affair with Arthur's chief knight Sir Lancelot, which first appears in Chrétien de Troyes' Lancelot, the Knight of the Cart. This motif was picked up in all the cyclical Arthurian literature, starting with the Lancelot-Grail Cycle of the early 13th century and carrying through the Post-Vulgate Cycle and Thomas Malory's Le Morte d'Arthur. Their betrayal of Arthur leads to the downfall of the kingdom.
The Welsh form Gwenhwyfar can be translated as The White Fay or White Ghost (Proto-Celtic *Uindā Seibrā, "white phantom" or "white fairy"; see also Ishara). Some have suggested that the name may derive from "Gwenhwy-fawr" or Gwenhwy the Great, contrasting the character to "Gwenhwy-fach" or Gwenhwy the less; Gwenhwyfach appears in Welsh literature as a sister of Gwenhwyfar, but in her scholarly edition of the Welsh Triads, Rachel Bromwich suggests this is a less likely etymology. Geoffrey of Monmouth renders her name Guanhumara in Latin. The name in Modern English is spelled Jennifer from the Cornish rendering.
In some adaptations, she is the daughter of King Leodegrance and is betrothed to Arthur early in his career, while he is garnering support. When Lancelot arrives later, she is instantly smitten, and they soon consummate the adultery that will bring about Arthur's fall. However, Arthur is not aware of their relationship or adultery for quite a while, until at a feast when he realizes that neither Lancelot nor Guinevere is there. Their affair is exposed by two of King Lot's sons, Agravain and Mordred, and Lancelot flees for his life while Arthur reluctantly sentences his queen to burn at the stake. Knowing Lancelot and his family will try to stop the execution, Arthur sends many of his knights to defend the pyre, though Gawain refuses to participate. Lancelot arrives and rescues the queen, and in the course of the battle Gawain's brothers Gaheris and Gareth are killed, sending Gawain into a rage so great that he pressures Arthur into war with Lancelot. When Arthur goes to France to fight Lancelot, he leaves Guinevere in the care of Mordred, who plots to marry the queen himself and take Arthur's throne. In some versions Guinevere assents to Mordred's proposal, but in others, she hides in the Tower of London and then takes refuge in a convent. Hearing of the treachery, Arthur returns to Britain and slays Mordred at Camlann, but his wounds are so severe that he is taken to the isle of Avalon. Guinevere meets Lancelot one last time, then returns to the convent where she spends the remainder of her life.
Guinevere is childless in most stories, two exceptions being the Perlesvaus and the Alliterative Morte Arthure. In the former, the character Loholt is apparently her son; he appears as Arthur's illegitimate son in other works. In the latter, Guinevere willingly becomes Mordred's consort and bears him two sons, though all of this is implied rather than stated in the text. There are mentions of Arthur's sons in the Welsh Triads, though their exact parentage isn't clear. Other family relations are equally obscure; a half-sister and a brother play the antagonists in the Lancelot-Grail and the German romance Diu Crône respectively, but neither character is mentioned elsewhere. Welsh tradition remembers the queen's sister Gwenhyvach and records the enmity between them. While later literature almost always names Leodegrance as Guinevere's father, her mother is usually unmentioned, though she is sometimes said to be dead. Such is the case in the Middle English romance The Awntyrs off Arthure (The Adventures of Arthur), in which the ghost of Guinevere's mother appears to her daughter and Gawain in Inglewood Forest. Other works name cousins of note, though these do not usually appear in more than one place.
Guinevere has been portrayed as everything from a weak and opportunistic traitor to a fatally flawed but noble and virtuous gentlewoman. In Chrétien's Yvain, the Knight of the Lion, she is praised for her intelligence, friendliness, and gentility, while in Marie de France's Lanval (and Thomas Chestre's Middle English version, Sir Launfal), she is a vindictive adulteress, disliked by the protagonist and all well-bred knights. The early chronicles tend to portray her inauspiciously or hardly at all, while later authors used her good and bad qualities to construct a deeper character who plays a larger role. The works of Chrétien were some of the first to elaborate on the character Guinevere beyond simply the wife of Arthur. This is likely due to his audience at the time, the court of Marie de Champagne, which was composed of courtly ladies who played highly social roles.
The earliest mention of Guinevere is in the Welsh tale Culhwch ac Olwen, where she appears as Arthur's queen, but little more is said about her. Caradoc of Llancarfan, who wrote his Life of Gildas before 1136, recounts how she was kidnapped by Melwas, king of the "Summer Country" (Aestiva Regio, perhaps meaning Somerset), and held prisoner at his stronghold at Glastonbury. The story states that Arthur spent a year searching for her, found her, and had assembled an army to storm Melwas' fort when Saint Gildas negotiated a peaceful resolution and reunited husband and wife. This is the earliest written account of Guinevere's abduction, one of the earliest and most common episodes in Arthurian legend. A seemingly related account appears carved into the archivolt of Modena Cathedral in Modena, Italy, which probably predates Caradoc's telling. Here, "Artus de Bretania" and Isdernus approach a tower in which "Mardoc" is holding "Winlogee", while on the other side Carrado (probably Carados) fights Galvagin (Gawain) while the knights Galvariun and Che (Kay) approach. "Isdernus" is most certainly some incarnation of Yder, a Celtic hero whose name appears in Culhwch and Olwen, and who was Guinevere's lover tesa in a nearly-forgotten tradition mentioned in Beroul's Tristan and reflected in the later Roman de Yder. The Welsh poet Dafydd ap Gwilym alludes to Guinevere's abduction in two of his poems, and the medievalist Roger Sherman Loomis suggested that this tale shows that "she had inherited the role of a Celtic Persephone".
Geoffrey of Monmouth tells a different version of Guinevere's abduction, adding that she was descended from a noble Roman family and was the ward of Cador, Duke of Cornwall. Arthur leaves her in the care of his nephew, Mordred while he crosses over to Europe to go to war with the (fictitious) Roman Procurator Lucius Hiberius. While he is absent, Mordred seduces Guinevere, declares himself king and takes her as his own queen; consequently, Arthur returns to Britain and fights Mordred at the fatal Battle of Camlann.
Chrétien de Troyes tells yet another version of Guinevere's abduction, this time by Meleagant (whose name is possibly derived from Melwas) in Lancelot, the Knight of the Cart. The abduction sequence is largely a reworking of that recorded in Caradoc's work, but here the queen's rescuer is not Arthur (or Yder) but Lancelot, whose adultery with the queen is dealt with for the first time in this poem. It has been suggested that Chrétien invented their affair to supply Guinevere with a courtly extramarital lover. Mordred could not be used, as his reputation was beyond saving, and Yder had been forgotten entirely.
In the German tale Diu Crône, Guinevere's brother Gotegrim kidnaps her and intends to kill her for refusing to marry Gasozein, who claims to be her rightful husband. In Ulrich von Zatzikhoven's Lanzelet, Valerin, King of the Tangled Wood, claims the right to marry her and carries her off to his castle in a struggle for power that reminds scholars of her prescient connections to the fertility and sovereignty of Britain. Arthur's company save her, but Valerin kidnaps her again and places her in a magical sleep inside another castle surrounded by snakes, where only the powerful sorcerer Malduc can rescue her. All of these similar tales of abduction by another suitor – and this allegory includes Lancelot, who whisks her away when she is condemned to burn at the stake for their adultery – are demonstrative of a recurring Hades-snatches-Persephone theme, positing that Guinevere is like the otherworld bride Étaín, who Midir, king of the Underworld, carries off from her earthly life after she has forgotten her past.
A version of the abduction of Guinevere is associated with Meigle in Scotland, known for its carved Pictish stelae. One of the stones, now in the Meigle Sculptured Stone Museum, is said to depict Vanora, the local name for Guinevere. She was said to have been abducted by King Mordred. When she was eventually returned to Arthur, he had her condemned to death for infidelity and ordered that she be torn to pieces by wild beasts, an event said to be depicted on Meigle Stone 2. This stone was one of two that originally stood near a mound that is identified as Vanora's grave.