One of many painting inspired by the pre-Arthurian tale of Tristan and Iseult. The story of Tristan, Iseult (or Isolde), and King Mark rivals the tales of King Arthur, Guinevere, and Sir Lancelot. The story can be found here to read online, or download. It’s also available in Greek, Finnish or as an audio book.
http://www.youtube.com/watch?v=J-qoaioG2UA