Book IX - Chapter XXXI - How Sir Tristram returned against King Arthur's party because he saw Sir Palomides on that party.
THEN upon the morn Sir Palomides returned from the King of Northgalis, and rode to King Arthur's side, where was King Carados, and the King of Ireland, and Sir Launcelot's kin, and Sir Gawaine's kin. So Sir Palomides sent the damosel unto Sir Tristram that he sent to seek him when he was out of his mind in the forest, and this damosel asked Sir Tristram what he was and what was his name? As for that, said Sir Tristram, tell Sir Palomides ye shall not wit as at this time unto the time I have broken two spears upon him. But let him wit thus much, said Sir Tristram, that I am the same knight that he smote down in over-evening at the tournament; and tell him plainly on what party that Sir Palomides be I will be of the contrary party. Sir, said the damosel, ye shall understand that Sir Palomides will be on King Arthur's side, where the most noble knights of the world be. In the name of God, said Sir Tristram, then will I be with the King of Northgalis, because Sir Palomides will be on King Arthur's side, and else I would not but for his sake. So when King Arthur was come they blew unto the field; and then there began a great party, and so King Carados jousted with the King of the Hundred Knights, and there King Carados had a fall: then was there hurling and rushing, and right so came in knights of King Arthur's, and they bare aback the King of Northgalis' knights.
Then Sir Tristram came in, and began so roughly and so bigly that there was none might withstand him, and thus Sir Tristram dured long. And at the last Sir Tristram fell among the fellowship of King Ban, and there fell upon him Sir Bors de Ganis, and Sir Ector de Maris, and Sir Blamore de Ganis, and many other knights. And then Sir Tristram smote on the right hand and on the left hand, that all lords and ladies spake of his noble deeds. But at the last Sir Tristram should have had the worse had not the King with the Hundred Knights been. And then he came with his fellowship and rescued Sir Tristram, and brought him away from those knights that bare the shields of Cornwall. And then Sir Tristram saw another fellowship by themself, and there were a forty knights together, and Sir Kay, the Seneschal, was their governor. Then Sir Tristram rode in amongst them, and there he smote down Sir Kay from his horse; and there he fared among those knights like a greyhound among conies.
Then Sir Launcelot found a knight that was sore wounded upon the head. Sir, said Sir Launcelot, who wounded you so sore? Sir, he said, a knight that beareth a black shield, and I may curse the time that ever I met with him, for he is a devil and no man. So Sir Launcelot departed from him and thought to meet with Sir Tristram, and so he rode with his sword drawn in his hand to seek Sir Tristram; and then he espied him how he hurled here and there, and at every stroke Sir Tristram wellnigh smote down a knight. O mercy Jesu! said the king, sith the times I bare arms saw I never no knight do so marvellous deeds of arms. And if I should set upon this knight, said Sir Launcelot to himself, I did shame to myself, and therewithal Sir Launcelot put up his sword. And then the King with the Hundred Knights and an hundred more of North Wales set upon the twenty of Sir Launcelot's kin: and they twenty knights held them ever together as wild swine, and none would fail other. And so when Sir Tristram beheld the noblesse or these twenty knights he marvelled of their good deeds, for he saw by their fare and by their rule that they had liefer die than avoid the field. Now Jesu, said Sir Tristram, well may he be valiant and full of prowess that hath such a sort of noble knights unto his kin, and full like is he to be a noble man that is their leader and governor. He meant it by Sir Launcelot du Lake. So when Sir Tristram had beholden them long he thought shame to see two hundred knights battering upon twenty knights. Then Sir Tristram rode unto the King with the Hundred Knights and said: Sir, leave your fighting with those twenty knights, for ye win no worship of them, ye be so many and they so few; and wit ye well they will not out of the field I see by their cheer and countenance; and worship get ye none an ye slay them. Therefore leave your fighting with them, for I to increase my worship I will ride to the twenty knights and help them with all my might and power. Nay, said the King with the Hundred Knights, ye shall not do so; now I see your courage and courtesy I will withdraw my knights for your pleasure, for evermore a good knight will favour another, and like will draw to like.