AS Sir Mordred was ruler of all England, he did do make letters as though that 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 was he crowned at Canterbury, and held a feast there fifteen days; and afterward he drew him unto Winchester, and there he took the Queen Guenever, and said plainly that he would wed her which was his uncle's wife and his father'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, to buy all manner of things that longed unto the wedding. And because of her fair speech Sir Mordred trusted her well enough, and gave her leave to go. And so 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 garnished it with men, and so kept it.

Then when Sir Mordred wist and understood 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, would never trust to come in his hands again.

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 farther but your mother's brother, and on her himself King Arthur begat you upon his own sister, therefore how may you wed your father's wife? Sir, said the noble clerk, leave this opinion or 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 an thou chafe me any more I shall make strike off thy head. So the Bishop departed and did the cursing in the most orgulist 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 sonds, 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 liefer slay herself than to be married with him. Then came word to Sir Mordred that King Arthur had araised the siege for Sir Launcelot, and he was coming homeward with a great host, to be avenged upon Sir Mordred; wherefore Sir Mordred made write writs to all the barony of this land, and much people drew to him. For then was the common voice among them that with Arthur was none other life but war and strife, and with Sir Mordred was great joy and bliss. Thus was Sir Arthur depraved, and evil said of. And many there were that King Arthur had made up of nought, and given them lands, might not then say him a good word. Lo ye all Englishmen, see ye not what a mischief here was! for he that was the most king and knight of the world, and most loved the fellowship of noble knights, and by him they were all upholden, now might not these Englishmen hold them content with him. Lo thus was the old custom and usage of this land; and also men say that we of this land have not yet lost nor forgotten that custom and usage. Alas, this is a great default of us Englishmen, for there may no thing please us no term. And so fared the people at that time, 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 to Dover, for there he heard say that Sir Arthur would arrive, and so he thought to beat his own father from his lands; and the most part of all England held with Sir Mordred, the people were so new-fangle.