How Sir Mordred presumed and took on him to be King of England, and would have married the queen, his father’s wife. 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 lo............