The cup of the last supper in which Joseph of Arimithea caught the blood of crucified Christ. It was, by legend, carried to Britain where it was hidden, entrusted to Joseph’s descendants, ending with Galahad. The search for the grail quest has become a metaphor for man’s search for purity and
grace ; the search for the grail forms the center of many Arthurian romances as the
knights strive to overcome flaws in their own character to achieve grace. This quest, laid out best in Wolfram von Eshenbach’s Parsifal and the
Vulgate Cycle , has been echoed many times.
However, there are contentions that the grail is not a cup at all; indeed that there is some dispute concerning whether medieval authors had any consensus to claim that it was a cup. See
What is the Grail? analysis from Dr.Linda A. Malcor THE CHALICE AT THE CROSS.