When Modred escaped from Sir Lancelot he got to horse, all wounded as he was, and never drew rein until he had found King Arthur, to whom he told all that had happened.
Then great was the King’s grief. Despite all that Modred could say, he was slow to doubt Sir Lancelot, whom he loved, but his mind was filled with forebodings; for many a knight had been slain and well he knew that their kin would seek vengeance on Sir Lancelot, and the noble fellowship of the Round Table be utterly destroyed by their feuds.
All too soon it proved even as the King had feared. Many were found to hold with Sir Modred; some because they were kin to the knights that had been slain, some from envy of the honor and worship of the noble Sir Lancelot; and among them even were those who dared to raise their voice against the Queen herself, calling for judgment upon her as leagued with a traitor against the King, and as having caused the death of so many good knights. Now in those days the law was that if any one were accused of treason by witnesses, or taken in the act, that one should die the death by burning, be it man or woman, knight or churl. So then the murmurs grew to a loud clamor that the law should have its course, and that King Arthur should pass sentence on the Queen. Then was the King’s woe doubled.
“For,” said he, “I sit as King to be a rightful judge and keep all the law; wherefore I may not do battle for my own Queen, and now there is none other to help her.”
So a decree was issued that Queen Guinevere should be burnt at the stake outside the walls of Carlisle.
Forthwith, King Arthur sent for his nephew, Sir Gawain, and said to him:
“Fair nephew, I give it in charge to you to see that all is done as has been decreed.”
But Sir Gawain answered boldly: “Sir King, never will I be present to see my lady the Queen die. It is of [ill counsel] that ye have consented to her death.”
Then the King bade Gawain send his two young brothers, Sir Gareth and Sir Gaheris, to receive his commands, and these he desired to attend the Queen to the place of execution. So Gareth made answer for both:
“My Lord the King, we owe you obedience in all things, but know that it is sore against our wills that we obey you in this; nor will we appear in arms in the place where that noble lady shall die”; then sorrowfully they mounted their horses and rode to Carlisle.