The Grail was a hot-button issue in his time, as it was in the 13th century, and the issue was the same in both cases -- whether the Grail legend was to be assimilated to Christian orthodoxy or whether it was going to remain independent, reflecting...something else. The character of Galahad was the vehicle for the Christian side of that quarrel -- and to this day, Galahad's the touchstone. Mystically minded Christians adore him; everyone else thinks he's an insufferable prig. ;-)