Sir Galahad is a knight of King Arthur's Round Table and one of the three achievers of the Holy Grail. He is the son of Sir Lancelot and Elaine and is renowned for his gallantry and purity as the most perfect of all knights.
The circumstances surrounding the conception of Galahad are myth. It happens when King Arthur's greatest knight, Lancelot, mistakes Elaine of Corbenic for his secret mistress, Queen Guinevere. King Pelles, Elaine’s father has already received magical foreknowledge that Lancelot will give his daughter a child and that this little boy will grow to become the greatest knight in the world, the knight chosen by God to discover the Holy Grail. Pelles also knows that Lancelot will only lie with his one true love, Guinevere. Destiny will have to be helped along a little so Pelles seeks out an enchantress who gives him a magic ring that will make Elaine take on the appearance of Guinevere. Lancelot and Elaine sleep together, but on discovering the deception, Lancelot leaves Elaine, but when he finds out that they have conceived a son together, he forgives her. "Galahad" was Lancelot's original name, but it was changed when Lancelot was a child. At his birth, therefore, Galahad is given his father's own original name. Merlin prophesies that Galahad will surpass his father in valor and be successful in his search for the Holy Grail.
Upon reaching adulthood, Galahad is reunited with his father Lancelot, who knights his son after being defeated by him. Galahad is then brought to King Arthur's court at Camelot , where he is accompanied by a very old knight who immediately leads him over to the Round Table and unveils an unused chair that has been kept vacant for the sole person who will succeed in the quest of the Holy Grail. For all others who have aspired to sit in the chair, it has proved to be immediately fatal. Galahad survives this test, witnessed by Arthur who, upon realizing the greatness of this new knight, leads him out to the river where a sword lies in a stone with an inscription reading "Never shall man take me hence but only he by whose side I ought hang; and he shall be the best knight of the world." This resembles the legends of Arthur's own sword, Excalibur. Galahad accomplishes this test with ease, and Arthur swiftly proclaims him to be the greatest knight in the world.
While all of the Knights of the Round Table set out to find the Holy Grail, it is Galahad who takes the initiative to begin the search for the Grail; the rest of the knights follow him. Arthur is sorrowful that all the knights have joined the quest as he believes that many will never return, dying on their quest. Galahad, in some ways, mirrors Arthur, drawing a sword from a stone in the way that Arthur did. In this manner, Galahad is seen to be the chosen one.
Galahad for the most part travels alone, smiting his enemies, rescuing Sir Percival from twenty knights and saving maidens in distress, until he is finally reunited with fellow knights, Bors and Percival. After many adventures, Galahad eventually finds the Grail. After seeing the Grail, Galahad, however, makes the request that he may die at the time of his choosing. So it is, while making his way back to Arthur's court with the Grail, Galahad makes his request to die. Galahad bids Percival and Bors farewell, and angels take him to Heaven, as witnessed by Bors and Percival. While it is not explicit that the Holy Grail is never to be seen again on earth, it is implied as there has since then been no knight capable of obtaining it. Galahad's success in the endeavor that was the search for the Holy Grail was predicted before his birth, by Merlin: Merlin had told Uther Pendragon that there was one who would find the Grail but that he was not yet born. At first this knight was believed to be Perceval; however it is later discovered to be Galahad. Galahad was conceived for the divine purpose of seeking the Holy Grail. But Galahad's conception happened through pure deceit; under a cloak of deception that was very similar, in fact, to that which led to the conception of Arthur. Despite this, Galahad is the knight who is chosen to find the Grail. Galahad is exalted above all the other knights; he is the one worthy enough to have the Holy Grail revealed to him and to ascend into heaven.