Guinevere was the legenary queen consort of King Arthur. Guinevere was also a great warrior beside the hand of King Arthur .She is 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.