Book III - Chapter VII - How the hart was chased into a castle and there slain, and how Sir Gawaine slew a lady.
THEN Gawaine and Gaheris rode more than a pace after the white hart, and let slip at the hart three couple of greyhounds, and so they chased the hart into a castle, and in the chief place of the castle they slew the hart; Sir Gawaine and Gaheris followed after. Right so there came a knight out of a chamber with a sword drawn in his hand and slew two of the greyhounds, even in the sight of Sir Gawaine, and the remnant he chased them with his sword out of the castle. And when he came again, he said, O my white hart, me repenteth that thou art dead, for my sovereign lady gave thee to me, and evil have I kept thee, and thy death shall be dear bought an I live. And anon he went into his chamber and armed him, and came out fiercely, and there met he with Sir Gawaine. Why have ye slain my hounds? said Sir Gawaine, for they did but their kind, and liefer I had ye had wroken your anger upon me than upon a dumb beast. Thou sayest truth, said the knight, I have avenged me on thy hounds, and so I will on thee or thou go. Then Sir Gawaine alighted afoot and dressed his shield, and struck together mightily, and clave their shields, and stoned their helms, and brake their hauberks that the blood ran down to their feet.
At the last Sir Gawaine smote the knight so hard that he fell to the earth, and then he cried mercy, and yielded him, and besought him as he was a knight and gentleman, to save his life. Thou shalt die, said Sir Gawaine, for slaying of my hounds. I will make amends, said the knight, unto my power. Sir Gawaine would no mercy have, but unlaced his helm to have stricken off his head. Right so came his lady out of a chamber and fell over him, and so he smote off her head by misadventure. Alas, said Gaheris, that is foully and shamefully done, that shame shall never from you; also ye should give mercy unto them that ask mercy, for a knight without mercy is without worship. Sir Gawaine was so stonied of the death of this fair lady that he wist not what he did, and said unto the knight, Arise, I will give thee mercy. Nay, nay, said the knight, I take no force of mercy now, for thou hast slain my love and my lady that I loved best of all earthly things. Me sore repenteth it, said Sir Gawaine, for I thought to strike unto thee; but now thou shalt go unto King Arthur and tell him of thine adventures, and how thou art overcome by the knight that went in the quest of the white hart. I take no force, said the knight, whether I live or I die; but so for dread of death he swore to go unto King Arthur, and he made him to bear one greyhound before him on his horse, and another behind him. What is your name? said Sir Gawaine, or we depart. My name is, said the knight, Ablamar of the Marsh. So he departed toward Camelot.