The closing years of the twelfth century witness the emergence of a new discourse in European, and especially French, vernacular literature. In about 1181 Chrétien de Troyes's final poetic work, known as the Conte du Graal or Perceval, introduces to the literary canon an object that, within that nascent discourse, comes to be known as the Grail or, later, the Holy Grail.

To deem the emergent discourse of the Grail an entirely autonomous phenomenon during this period would not be entirely accurate however; the new literary object that appears so suddenly and enigmatically in Chrétien's poem grafts itself in a quasi-parasitic fashion on to an already established literary tradition, that of Arthurian courtly literature. Indeed, Arthurian literature subsequent to, and influenced by, Chrétien's unfinished text gradually accords ever more prominence to the theme of the Grail, and in doing so undergoes a marked Christianization. By the date of composition of the Vulgate Queste del Saint Graal, some forty to fifty years after Chrétien's poem, the Arthurian milieu has become little more than the passive host for a militant evangelism built around the discourse of the Grail. Indeed, as Thomas Kelly has observed, ‘during the period from 1180 to 1235 remarkable transformations occur in Arthurian romance’. This half-century represents the chronological scope of this book, and the transformations that occur during this period can, I suggest, be largely imputed to the appearance of the literary Grail.