The document discusses the legend of the Holy Grail according to Christian tradition and medieval literature. It was the dish or cup used by Jesus at the Last Supper or to collect his blood at the crucifixion. According to legend, it was brought to England by Joseph of Arimathea and guarded by the Fisher King. The search for the Holy Grail by Arthur's knights became a test of purity and virtue. The document also discusses the origins of the legend in earlier Celtic mythology involving magical vessels and relics.