Tristan should not have loved Isolde, nor Isolde Tristan, for she was chosen by King Mark. It is only for this reason, as Rosemary Sutcliff suggests, that the courtly medieval storytellers included the motif of the love potion accidentally consumed by both. She draws on the old, wild, darker Celtic original and beautifully narrates how the deep love between the Irish princess Yseult and the Cornish hero Tristan develops.