So he departed from him with Sir Driant, and by the way they met with a knight that was sent from Morgan le Fay unto King Arthur; and this knight had a fair horn harnessed with gold, and the horn had such a virtue that there might no lady nor gentlewoman drink of that horn but if she were true to her husband, and if she were false she should spill all the drink, and if she were true to her lord she might drink peaceable. And because of the Queen Guenever, and in the despite of Sir Launcelot, this horn was sent unto King Arthur; and by force Sir Lamorak made that knight to tell all the cause why he bare that horn. Now shalt thou bear this horn, said Lamorak, unto King Mark, or else choose thou to die for it; for I tell thee plainly, in despite and reproof of Sir Tristram thou shalt bear that horn unto King Mark, his uncle, and say thou to him that I sent it him for to assay his lady, and if she be true to him he shall prove her. So the knight went his way unto King Mark, and brought him that rich horn, and said that Sir Lamorak sent it him, and thereto he told him the virtue of that horn. Then the king made Queen Isoud to drink thereof, and an hundred ladies, and there were but four ladies of all those that drank clean. Alas, said King Mark, this is a great despite, and sware a great oath that she should be burnt and the other ladies.

Then the barons gathered them together, and said plainly they would not have those ladies burnt for an horn made by sorcery, that came from as false a sorceress and witch as then was living. For that horn did never good, but caused strife and debate, and always in her days she had been an enemy to all true lovers. So there were many knights made their avow, an ever they met with Morgan le Fay, that they would show her short courtesy. Also Sir Tristram was passing wroth that Sir Lamorak sent that horn unto King Mark, for well he knew that it was done in the despite of him. And therefore he thought to quite Sir Lamorak.

Then Sir Tristram used daily and nightly to go to Queen Isoud when he might, and ever Sir Andred his cousin watched him night and day for to take him with La Beale Isoud. And so upon a night Sir Andred espied the hour and the time when Sir Tristram went to his lady. Then Sir Andred gat unto him twelve knights, and at midnight he set upon Sir Tristram secretly and suddenly and there Sir Tristram was taken naked abed with La Beale Isoud, and then was he bound hand and foot, and so was he kept until day. And then by the assent of King Mark, and of Sir Andred, and of some of the barons, Sir Tristram was led unto a chapel that stood upon the sea rocks, there for to take his judgment: and so he was led bounden with forty knights. And when Sir Tristram saw that there was none other boot but needs that he must die, then said he: Fair lords, remember what I have done for the country of Cornwall, and in what jeopardy I have been in for the weal of you all; for when I fought for the truage of Cornwall with Sir Marhaus, the good knight, I was promised for to be better rewarded, when ye all refused to take the battle; therefore, as ye be good gentle knights, see me not thus shamefully to die, for it is shame to all knighthood thus to see me die; for I dare say, said Sir Tristram, that I never met with no knight but I was as good as he, or better. Fie upon thee, said Sir Andred, false traitor that thou art, with thine avaunting; for all thy boast thou shalt die this day. O Andred, Andred, said Sir Tristram, thou shouldst be my kinsman, and now thou art to me full unfriendly, but an there were no more but thou and I, thou wouldst not put me to death. No! said Sir Andred, and therewith he drew his sword, and would have slain him.

When Sir Tristram saw him make such countenance he looked upon both his hands that were fast bounden unto two knights, and suddenly he pulled them both to him, and unwrast his hands, and then he leapt unto his cousin, Sir Andred, and wrested his sword out of his hands; then he smote Sir Andred that he fell to the earth, and so Sir Tristram fought till that he had killed ten knights. So then Sir Tristram gat the chapel and kept it mightily. Then the cry was great, and the people drew fast unto Sir Andred, mo than an hundred. When Sir Tristram saw the people draw unto him, he remembered he was naked, and sperd fast the chapel door, and brake the bars of a window, and so he leapt out and fell upon the crags in the sea. And so at that time Sir Andred nor none of his fellows might get to him, at that time.