Thus as Sir Tristram and La Beale Isoud were in prison, it happed a knight and a lady came unto them where they were, to cheer them. I have marvel, said Tristram unto the knight and the lady, what is the cause the lord of this castle holdeth us in prison: it was never the custom of no place of worship that ever I came in, when a knight and a lady asked harbour, and they to receive them, and after to destroy them that be his guests. Sir, said the knight, this is the old custom of this castle, that when a knight cometh here he must needs fight with our lord, and he that is weaker must lose his head. And when that is done, if his lady that he bringeth be fouler than our lord’s wife, she must lose her head: and if she be fairer proved than is our lady, then shall the lady of this castle lose her head. So God me help, said Sir Tristram, this is a foul custom and a shameful. But one advantage have I, said Sir Tristram, I have a lady is fair enough, fairer saw I never in all my life-days, and I doubt not for lack of beauty she shall not lose her head; and rather than I should lose my head I will fight for it on a fair field. Wherefore, sir knight, I pray you tell your lord that I will be ready as to-morn with my lady, and myself to do battle, if it be so I may have my horse and mine armour.