As Sir Mordred was ruler of all England, he caused letters to be made as though they came from beyond the sea, and the letters specified that King Arthur was slain in battle with Sir Launcelot; wherefore Sir Mordred made a parliament, and called the lords together, and there he made them to choose him king. And so he was crowned at Canterbury, and held a feast there fifteen days. And afterwards he drew him to Winchester, and there he took Queen Guenever, and said plainly that he would wed her which was his uncle's wife; and so he made ready for the feast, and a day prefixed that they should be wedded. Wherefore Queen Guenever was passing heavy; but she durst not discover her heart, but spake fair and agreed to Sir Mordred's will. Then she desired of Sir Mordred for to go to London for to buy all manner thing that belonged unto the wedding; and because of her fair speech, Sir Mordred trusted her well enough, and gave her leave to go. And when she came to London, she took the Tower of London, and suddenly in all haste possible she stuffed it with all manner of victual and well filled it with men, and so kept it. Then when Sir Mordred wist how he was beguiled, he was passing wroth out of measure. And, a short tale for to make, he went and laid a mighty siege about the Tower of London, and made many great assaults thereat, and threw many great engines unto them, and shot great guns. But all might not prevail Sir Mordred, for Queen Guenever would never for fair speech nor for foul trust to come in his hands again. And then came the bishop of Canterbury, the which was a noble clerk and an holy man, and thus he said to Sir Mordred: "Sir, what will ye do, will ye first displease God, and sithen shame yourself and all knighthood? Is not King Arthur your uncle, no further but your mother's brother? Leave this opinion, or else I shall curse you with book, and bell, and candle."
"Do thou thy worst," said Sir Mordred, "wit thou well I shall defy thee."
"Sir," said the bishop, "and wit you well I shall not fear me to do that me ought to do. Also where ye noise where my lord Arthur is slain, and that is not so, and therefore ye will make a foul work in this land."
"Peace, thou false priest," said Sir Mordred, "for, and thou chafe me any more, I shall make strike off thy head."
So the bishop departed, and did the curse in the most orgulous wise that might be done. And then Sir Mordred sought the bishop of Canterbury for to have slain him. Then the bishop fled, and took part of his goods with him, and went nigh unto Glastonbury, and there he was as priest hermit in a chapel, and lived in poverty and in holy prayers: for well he understood that mischievous war was at hand. Then Sir Mordred sought on Queen Guenever by letters and by fair means and foul means, for to have her to come out of the Tower of London, but all this availed not, for she answered him shortly, openly and privily, that she had liever slay herself than to be married with him. Then came word to Sir Mordred that King Arthur had raised the siege from Sir Launcelot, and that he was coming homeward with a great host, for to be avenged upon Sir Mordred. Wherefore Sir Mordred made to write letters unto all the barony of this land, and much people drew unto him; for then was the common voice among them, that with King Arthur was none other life but war and strife, and with Sir Mordred was great joy and bliss. Thus was King Arthur depraved and evil said of, and many there were that King Arthur had made up of nought, and had given them lands, might not say of him then a good word.
Lo, we all Englishmen see what a mischief here was; for he that was the noblest king and knight of the world, and most loved the fellowship of noble knights and men of worship, and by him they were all upholden, now might not we Englishmen hold us content with him. Lo, this was the old custom and usage of this land. And also men say that we of this land have not yet lost nor forgotten the custom and usage. Alas! alas! this is a great default of us Englishmen, for there may nothing please us no term. And so fared the people at that time. For they were better pleased with Sir Mordred than they were with King Arthur, and much people drew unto Sir Mordred, and said they would abide with him for better and for worse. And so Sir Mordred drew with a great host towards Dover, for there he heard say that King Arthur would arrive. And the most part of all England held with Sir Mordred, the people were so new-fangled.
And so, as Sir Mordred was at Dover with his host, there came King Arthur with a great navy of ships, galleys, and carracks. And there was Sir Mordred ready awaiting upon his landing, to let [hinder] his own [uncle] to land upon the land that he was king over. Then there was launching of great boats and small, and full of noble men of arms, and there was much slaughter of gentle knights, and many a full bold baron was laid full low on both parties. But King Arthur was so courageous, that there might no manner of knights let him to land, and his knights fiercely followed him. And so they landed, maugre Sir Mordred and all his power, and put Sir Mordred aback, that he fled and all his people. So when this battle was done, King Arthur let bury his people that were dead, and then was the noble knight Sir Gawaine found in a great boat lying more than half dead. When Sir Arthur wist that Sir Gawaine was laid so low, he went unto him, and there the king made sorrow out of measure, and took Sir Gawaine in his arms, and thrice he there swooned. And when he awaked he said, "Alas, Sir Gawaine, my sister's son, here now thou liest, the man in the world that I loved most, and now is my joy gone: for now, my nephew Sir Gawaine, I will discover me unto your person; in Sir Launcelot and you I most had my joy, and mine affiance, and now have I lost my joy of you both, wherefore all mine earthly joy is gone from me."
"Mine uncle King Arthur," said Sir Gawaine, "wit you well, my death day is come, and all is through mine own hastiness and wilfulness, for I am smitten upon the old wound the which Sir Launcelot gave me, on the which I feel well I must die, and had Sir Launcelot been with you as he was, this unhappy war had never begun, and of all this am I causer, for Sir Launcelot and his blood through their prowess held all your cankered enemies in subjection and danger: and now," said Sir Gawaine, "ye shall miss Sir Launcelot. But, alas, I would not accord with him, and therefore," said Sir Gawaine, "I pray you, fair uncle, that I may have paper, pen, and ink, that I may write unto Sir Launcelot a letter with mine own hands."
And when paper and ink was brought, Sir Gawaine was set up weakly by King Arthur, for he had been shriven a little before; and he wrote thus unto Sir Launcelot: "Flower of all noble knights that ever I heard of or saw in my days; I, Sir Gawaine, King Lot's son of Orkney, sister's son unto the noble King Arthur, send unto thee greeting, and let thee have knowledge, that the tenth day of May I was smitten upon the old wound which thou gavest me before the city of Benwick, and through the same wound that thou gavest me I am come unto my death day, and I will that all the world wit that I Sir Gawaine, knight of the Round Table, sought my death, and not through thy deserving, but it was mine own seeking; wherefore I beseech thee, Sir Launcelot, for to return again unto this realm and see my tomb, and pray some prayer more or less for my soul. Also, Sir Launcelot, for all the love that ever was between us, make no tarrying, but come over the sea in all the haste that thou mayest with thy noble knights, and rescue that noble king that made thee knight, that is my lord and uncle King Arthur, for he is full straitly bestood [sore beset] with a false traitor, which is my half brother Sir Mordred, and he hath let crown himself king, and he would have wedded my lady Queen Guenever, and so had he done, if she had not put herself in the Tower of London. And so the tenth day of May last past, my lord and uncle King Arthur and we all landed upon them at Dover, and there we put that false traitor Sir Mordred to flight. And there it misfortuned me for to be stricken upon thy stroke. And at the date of this letter was written but two hours and half before my death, written with mine own hand, and so subscribed with part of my heart's blood. And I require thee, most famous knight of all the world, that thou wilt see my tomb."