What is the significance of sir Lancelot and the quest of the holy quest?

Question- What is the significance of sir Lancelot and the quest of the holy quest?​

Answer- The Grail story is written around the end of the 12th century in a work by Robert de Borron . He wrote an early history of the Grail in his ‘Joseph of Arimathea', and identifies the Grail as the cup used at the Last Supper. The Grail is brought to Britain, where it is connected with the setting up of the Round Table by King Arthur's father, Uther Pendragon.  Sir Thomas Malory in his book (Death of Arthur) has had the greatest influence in the passing down of this legend. In it, King Arthur has been told that a particular seat at the Round Table will be filled by a knight who finds the Holy Grail. A stone is found with a sword firmly set into the centre of it. None of the existing knights can budge the sword, until Sir Galahad, son of Sir Lancelot, arrives at the Round Table. He can remove the sword. King Arthur and his knights set out on a quest to find the Holy Grail.  The Grail a vision of God that can been seen only if the viewer has led a pure life. Lancelot, because of his adultery with Queen Guinevere, can only see the Grail a a fuzzy outline in a dream. Perceval, who committed only one sin, is permitted only to see it in visions. Galahad alone is able to look into the Grail itself and to see what no other man can . After his vision Galahad dies, and the other knights return to Camelot.

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