Two larger stories intermesh in the Matter of Britain. One concerns Camelot, usually envisioned as a doomed utopia of chivalric virtue, undone by the fatal flaws of Arthur and Sir Lancelot. The other concerns the quests of the various knights to achieve the Holy Grail; some succeed (Galahad, Parsifal), and others fail (Lancelot). The mediaeval tale of Arthur and his knights is full of Christian themes; those themes involve the destruction of human plans for virtue by the moral failures of their authors, and the quest for an important Christian relic. Finally, the relationships between the characters invited treatment in the tradition of courtly love, such as Lancelot and Guinevere, or Tristan and Isolde. In more recent years, the trend has been to attempt to link the tales of King Arthur and his knights with Celtic mythology, usually in highly romanticized, early twentieth century reconstructed versions.