In the "Queste Del Saint Graal", Lancelot can't look directly at the Holy Grail because of his affair with her
[DOC] [TLE] The Parzival Legend - GEOCITIES.ws [PAR] In Search of the Holy Grail: The Parzival Legend ... First there was the Queste del 
Saint Graal, and then the Estoire del Saint ... is the disqualification of most of the 
knights because of their secular character.