When ready they took their horses and rode back to the lists, where Isolde and Palamides noted their entrance. When the Saracen saw that Tristram was disguised, a new fancy came into his scheming brain. Leaving the lists, he rode to where a knight sat sorely wounded under a tree outside. Him he prayed for an exchange of armor, saying that his own was too well known in the field, and that he wished for a disguise. "That is very true," said the knight, as he recognized the green armor. "You have made your array somewhat too well known. You are welcome to my arms, if they will be of use to you. They will gain more credit in your hands than they have won in mine." Palamides thereupon exchanged armor with him, and, taking his shield, which shone like silver, rode into the field. He now joined the party of King Arthur, and rode spitefully against Tristram, who had just struck down three knights. They met with such force that both spears splintered to their hands, though neither lost his seat. Then they dashed eagerly together with drawn swords and fought with the courage and fury of two lions. But Tristram wondered much what knight this was that faced him so valiantly, and grew angry as he felt that he was wasting in this single combat the strength he wished to treasure up for the day's work. La Belle Isolde, who had watched Palamides from her window, had seen him change his armor with the wounded knight. And when his treacherous purpose came to her mind she wept so heartily and was so deeply disturbed that she swooned away. At this juncture in the fray Lancelot rode again into the field, and when the knights of Arthur's party saw him the cry went up. "Return, return, here comes Sir Lancelot du Lake!" And some said to him, "Sir Lancelot, yonder knight in the black harness is your man. He is the best of our opponents, and has nearly overcome the good knight with the silver shield." At this Lancelot rode between the combatants, and cried to Palamides,-- "Let me have this battle; you need repose." Palamides knew Lancelot, and readily gave way, hoping through his mighty aid to gain revenge upon his rival. Then Lancelot fell upon Tristram, and, unknowing who he was, dealt him blows that would have stunned a less hardy fighter. Tristram returned them but feebly, for he knew well with whom he fought. And Isolde, who saw it all, was half out of her mind with grief. Dinadan now told Gareth who the knight in black armor was, and said, "Lancelot will get the better of him, for one is weary and the other fresh, and Tristram is not fighting with his old vim. Let us to his aid." "I am with you," said Gareth. "Yonder fellow with the silver shield is waiting to fall on Tristram, if he can to advantage. It is our business to give our friend what help we can." Then they rode in, and Gareth struck Lancelot a sword-blow that made his head swim, while Dinadan followed with a spear-thrust that bore horse and man together to the earth.