Le Morte dArthur Vol. 2 Chap. 11.7
CHAPTER VII. How Dame Elaine, Galahad's mother, came in great estate           unto Camelot, and how Sir Launcelot behaved him there.

    AND when Dame Elaine, the daughter of King Pelles, heard of this feast she went to her father and required him that he would give her leave to ride to that feast. The king answered: I will well ye go thither, but in any wise as ye love me and will have my blessing, that ye be well beseen in the richest wise; and look that ye spare not for no cost; ask and ye shall have all that you needeth. Then by the advice of Dame Brisen, her maiden, all thing was apparelled unto the purpose, that there was never no lady more richlier beseen. So she rode with twenty knights, and ten ladies, and gentlewomen, to the number of an hundred horses. And when she came to Camelot, King Arthur and Queen Guenever said, and all the knights, that Dame Elaine was the fairest and the best beseen lady that ever was seen in that court. And anon as King Arthur wist that she was come he met her and saluted her, and so did the most part of all the knights of the Round Table, both Sir Tristram, Sir Bleoberis, and Sir Gawaine, and many more that I will not rehearse. But when Sir Launcelot saw her he was so ashamed, and that because he drew his sword on the morn when he had lain by her, that he would not salute her nor speak to her; and yet Sir Launcelot thought she was the fairest woman that ever he saw in his life-days.

    But when Dame Elaine saw Sir Launcelot that would not speak unto her she was so heavy that she weened her heart would have to-brast; for wit you well, out of measure she loved him. And then Elaine said unto her woman, Dame Brisen: the unkindness of Sir Launcelot slayeth me near. Ah, peace, madam, said Dame Brisen, I will undertake that this night he shall lie with you, an ye would hold you still. That were me liefer, said Dame Elaine, than all the gold that is above the earth. Let me deal, said Dame Brisen. So when Elaine was brought unto Queen Guenever either made other good cheer by countenance, but nothing with hearts. But all men and women spake of the beauty of Dame Elaine, and of her great riches.

    Then, at night, the queen commanded that Dame Elaine should sleep in a chamber nigh her chamber, and all under one roof; and so it was done as the queen commanded. Then the queen sent for Sir Launcelot and bade him come to her chamber that night: Or else I am sure, said the queen, that ye will go to your lady's bed, Dame Elaine, by whom ye gat Galahad. Ah, madam, said Sir Launcelot, never say ye so, for that I did was against my will. Then, said the queen, look that ye come to me when I send for you. Madam, said Launcelot, I shall not fail you, but I shall be ready at your commandment. This bargain was soon done and made between them, but Dame Brisen knew it by her crafts, and told it to her lady, Dame Elaine. Alas, said she, how shall I do? Let me deal, said Dame Brisen, for I shall bring him by the hand even to your bed, and he shall ween that I am Queen Guenever's messenger. Now well is me, said Dame Elaine, for all the world I love not so much as I do Sir Launcelot.