The Demanda do Santo Graal (Quest for the Holy Grail) exists as a fifteenthcentury copy of a manuscript from the preceding era consisting of the Portuguese translation (possibly direct) of a French original. It is thought that the latter, in its most complete form, has disappeared. The integral state of the text in its current manuscript form (MS 2594 of the National Library of Vienna) allows us to discuss the transformation processes (and the reasons for them) through which the matière de Bretagne must have passed to arrive at this point, for it contains numerous modifications when compared with its sources, both recent and remote. The Christian intervention, taking advantage of the power of the myth conveyed by the story of the Grail from its origin, was without doubt one of the main factors in these changes. The creation of a lineage from Joseph of Arimathia to chivalric times and the attribution of a eucharistic nature to the object called the Grail are confirmation of this process of transformation of the story and the myth by intellectually active sectors of the Church in the first centuries of this millennium.

But the Christianisation did not stop there. The thirteenth century saw the configuration of two great cycles in which the chivalric matière was subjected to more profound organisation and unification. Its very structure passed through the sieve of increasingly strong religious intervention.

Let me recapitulate. The first of these cycles, now known as the Vulgate Cycle (1215–35) or Lancelot-Grail, centres around the journey of Arthur's greatest hero, from infancy through his adventures at court until his death, including the tensions between Lancelot and King Arthur and culminating in the downfall of the kingdom. Between the beginning (Lancelot) and the end (Mort Artu) of this trajectory is the narrative (Queste del Saint Graal) of the figure of Galahad, the great knight's son whose moral consistency distinguishes him from his father (in the context of the Cycle, of course) without eclipsing his father's importance or worth. Thus the Lancelot–Queste del Saint Graal–Mort Artu trilogy, which forms the fundamental and innovative part of this ensemble, cannot free itself from the powerful presence of the greatest hero of earthly chivalry, despite the moralising nature of the second book.