The legend of 
Tristan and Iseult is an influential romance and  tragedy, retold in numerous sources with as many variations. The tragic  story of the adulterous love between the Cornish knight Tristan  (Tristram) and the 
Irish  princess Iseult (Isolde, Yseut, etc.), the narrative predates and most  likely influenced the Arthurian romance of Lancelot and Guinevere, and  has had a substantial impact on Western art and literature since it  first appeared in the twelfth century. While the details of the story  differ from one author to another, the overall plot structure remains  much the same. The cosmic theme of conflict between good and 
evil,  betrayal and loyalty, self-interest and selflessness, both externally  and internally, as the best and the worst within heroes and struggles  for dominance, is never far from the reader's mind. In different forms,  as drama, opera, poetry, and prose, the tale has had an enduring  attraction and has long since taken its place as a classic within the  European literary heritage.