The grail and Morte D'Arthur made me think of The Questing Beast Glatisant, so I did some questing and offer a link for those who may be interested.

http://www.employees.org/~pcorless/pendragon/glatisant.txt

This was the most informative of all the links I found.

I also came across references to the Lancelot-Vulgate and Post-Vulgate Quest for the Holy Grail legends - all new to me; looking in Amazon I was distressed by the prices for a translation of these works. I am amazed at not having come across them before. I have a good copy of Mallory but these predate him, seem to be better written than Geoffrey of Monmouth's even earlier work, and I lust after them!