When king Arthur heard Of the coming of Guenever and the hundred knights with the Table Round, then king Arthur made great joy for their coming, and that rich present, and said openly, This fair lady is passing welcome unto me, for I have loved her long, and therefore there is nothing so lief to me. And these knights with the Round Table please me more than right great riches. And in all haste the king let ordain for the marriage and the coronation in the most honourablest wise that could be devised. Now Merlin, said king Arthur, go thou and espy me in all this land fifty knights which be of most prowess and worship. Within short time Merlin had found such knights that should fulfil twenty and eight knights, but no more he could find. Then the bishop of Canterbury was fetched, and he blessed the sieges with great royalty and devotion, and there set the eight and twenty knights in their sieges. And when this was done Merlin said, Fair sirs, ye must all arise and come to king Arthur for to do him homage; he will have the better will to maintain you. And so they arose and did their homage. And when they were gone Merlin found in every siege letters of gold that told the knights' names that had sitten therein. But two sieges were void: And so anon came young Gawaine, and asked the king a gift. Ask, said the king, and I shall grant it you. Sir, I ask that ye will make me knight that same day ye shall wed fair Guenever. I will do it with a good will, said king Arthur, and do unto you all the worship that I may, for I must by reason you are my nephew, my sister's son.
It is now the Vigil of the feast of Pentecost, and the knights are all at Arthur's court. Sir Launcelot is suddenly desired to go on a mission by a fair damsel who takes him to a forest and an abbey.
Book XIII. Chapter 1.
Truly, said Sir Launcelot, a gentlewoman brought me hither, but I know not the cause. In the meanwhile, as they thus stood talking together, there came twelve nuns which brought with them Galahad, the which was passing fair and well made, that unneth in the world men might not find his match; and all those ladies wept. Sir, said the ladies, we bring you here this child, the which we have nourished, and we pray you to make him a knight; for of a more worthier man's hand may he not receive the order of knighthood. Sir Launcelot beheld that young squire, and saw him seemly and demure as a dove, with all manner of good features, that he wend of his age never to have seen so fair a man of form. Then said Sir Launcelot, Cometh this desire of himself? He and all they said, Yea. Then shall he, said Sir Launcelot, receive the high order of knighthood as tomorrow at the reverence of the high feast. That night Sir Launcelot had passing good cheer, and on the morn at the hour of prime, at Galahad's desire, he made him knight, and said, God make him a good man, For beauty faileth you not as any that liveth.
Sir Launcelot returns to court. It is noticed that the back of the "siege (seat) perilous," at the Round Table has a new inscription saying that this day this long unfilled seat should be filled. Before sitting down to feast on this day, it was an old custom to see "some adventure."
Book XIII. Chapter 2.
So as they stood speaking, in came a squire, and said unto the king, Sir, I bring unto you marvellous tidings. What be they? said the king. Sir, there is here beneath at the river a great stone, which I saw fleet above the water, and therein saw I sticking a sword. The king said, I will see that marvel. So all the knights went with him, and when they came unto the river, they found there a stone fleeting, as it were of red marble, and therein stack a fair and a rich sword, and in the pomell thereof were precious stones, wrought with subtil letters of gold. Then the barons read the letters, which said in this wise: Never shall man take me hence but only he by whose side I ought to hang, and he shall be the best knight of the world. When the king had seen these letters, he said unto Sir Launcelot, Fair sir, this sword ought to be yours, for I am sure ye be the best knight of the world. Then Sir Launcelot answered full soberly: Certes, sir, it is not my sword: also, sir, wit ye well I have no hardiness to set my hand to, for it longed not to hang by my side. Also who that assayeth to take that sword, and falleth of it, he shall receive a wound by that sword, that he shall not be whole long after. And I will that ye wit that this same day will the adventures of the Sancgreal, that is called the holy vessel, begin.
Sir Gawaine tries to draw out the sword but fails. They sit at table and an old man brings in the young knight, Sir Galahad.
Book XIII. Chapter 4.
Then the old man made the young man to unarm him; and he was in a coat of red sendel, and bare a mantle upon his shoulder that was furred with ermine, and put that upon him. And the old knight said unto the young knight, Sir, follow me. And anon he led him unto the siege perilous, where beside sat Sir Launcelot, and the good man lift up the cloth, and found there letters that said thus: This is the siege of Galahad the haut prince. Sir, said the old knight, wit ye well that place is yours. And then he set him down surely in that siege . . . . . . . . . Then all the knights of the Table Round marvelled them greatly of Sir Galahad, that he durst sit there in that siege perilous, and was so tender of age, and wist not from whence he came, but all only by God, and said, This is he by whom the Sancgreal shall be achieved, for there sat never none but he, but he were mischieved.