NOW turn we from this matter, and speak we of Sir Tristram, of whom this book is principally of, and leave we the king and the queen, Sir Launcelot, and Sir Lamorak, and here beginneth the treason of King Mark, that he ordained against Sir Tristram. There was cried by the coasts of Cornwall a great tournament and jousts, and all was done by Sir Galahalt the haut prince and King Bagdemagus, to the intent to slay Launcelot, or else utterly destroy him and shame him, because Sir Launcelot had always the higher degree, therefore this prince and this king made this jousts against Sir Launcelot. And thus their counsel was discovered unto King Mark, whereof he was full glad.

Then King Mark bethought him that he would have Sir Tristram unto that tournament disguised that no man should know him, to that intent that the haut prince should ween that Sir Tristram were Sir Launcelot. So at these jousts came in Sir Tristram. And at that time Sir Launcelot was not there, but when they saw a knight disguised do such deeds of arms, they weened it had been Sir Launcelot. And in especial King Mark said it was Sir Launcelot plainly. Then they set upon him, both King Bagdemagus, and the haut prince, and their knights, that it was wonder that ever Sir Tristram might endure that pain. Notwithstanding for all the pain that he had, Sir Tristram won the degree at that tournament, and there he hurt many knights and bruised them, and they hurt him and bruised him wonderly sore. So when the jousts were all done they knew well that it was Sir Tristram de Liones; and all that were on King Mark's party were glad that Sir Tristram was hurt, and the remnant were sorry of his hurt; for Sir Tristram was not so behated as was Sir Launcelot within the realm of England.

Then came King Mark unto Sir Tristram and said: Fair nephew, I am sorry of your hurts. Gramercy my lord, said Sir Tristram. Then King Mark made Sir Tristram to be put in an horse bier in great sign of love, and said: Fair cousin, I shall be your leech myself. And so he rode forth with Sir Tristram, and brought him to a castle by daylight. And then King Mark made Sir Tristram to eat. And then after he gave him a drink, the which as soon as he had drunk he fell asleep. And when it was night he made him to be carried to another castle, and there he put him in a strong prison, and there he ordained a man and a woman to give him his meat and drink. So there he was a great while.

Then was Sir Tristram missed, and no creature wist where he was become. When La Beale Isoud heard how he was missed, privily she went unto Sir Sadok, and prayed him to espy where was Sir Tristram. Then when Sadok wist how Sir Tristram was missed, and anon espied that he was put in prison by King Mark and the traitors of Magouns, then Sadok and two of his cousins laid them in an ambushment, fast by the Castle of Tintagil, in arms. And as by fortune, there came riding King Mark and four of his nephews, and a certain of the traitors of Magouns. When Sir Sadok espied them he brake out of the bushment, and set there upon them. And when King Mark espied Sir Sadok he fled as fast as he might, and there Sir Sadok slew all the four nephews unto King Mark. But these traitors of Magouns slew one of Sadok's cousins with a great wound in the neck, but Sadok smote the other to the death. Then Sir Sadok rode upon his way unto a castle that was called Liones, and there he espied of the treason and felony of King Mark. So they of that castle rode with Sir Sadok till that they came to a castle that hight Arbray, and there in the town they found Sir Dinas the Seneschal, that was a good knight. But when Sir Sadok had told Sir Dinas of all the treason of King Mark he defied such a king, and said he would give up his lands that he held of him. And when he said these words all manner knights said as Sir Dinas said. Then by his advice and of Sir Sadok's, he let stuff all the towns and castles within the country of Liones, and assembled all the people that they might make.