The Sun is principal and Central;
The Moon is principal and surpassing.
My favorite version of the Arthurian legends is the The Quest for the Holy Grail written in the early 13th century. This story is interpreted from the Cistercian perspective and it is, therefore, less romantic than other Arthurian stories. Galahad, who is descended from King David through Lancelot and Joseph of Arimethea through the daughter of the last Fisher King (Keeper of the Grail), by the grace of God, is a virgin with a perfect virtue which allows him to partake in a ritual with the Grail and then leave his mortal frame.
The Knight, himself obscured,
Does not enter into poverty.
This version makes Galahad in the "resemblance of Christ" in the way he was expected in the Book of Revelation. Galahad's perfection serves as contrast to the other knights' flaws which are similar to flaws most of us mere mortals have. The knights who are most often considered the greatest show their greatest flaws in this quest. Gawain is brave and ambitious but nothing really mystically significant ever happens to him. Lancelot has mystical experiences which only make him feel remorse for all his sins with Guinevere.
Perceval is innocent but stupid. He is allowed to accompany Galahad for all but the very last of the adventure. Bors is similarly honored for his good common sense and sincerity. Bors is the knight who survives to tell Arthur's court of Galahad's adventures in which every action, person and object is not what it seems but represents other realities on many levels.1 The story is definitely inspiring to we modern day Don Quixotes.
1 Churchill, Winston S. The Birth of Britain; Bantam Books; 1956.