Book III - Chapter V - How at feast of the wedding of King Arthur to Guenever, a white hart came into the hall, and thirty couple hounds, and how a brachet pinched the hart which was taken away.
THEN was the high feast made ready, and the king was wedded at Camelot unto Dame Guenever in the church of Saint Stephen's, with great solemnity. And as every man was set after his degree, Merlin went to all the knights of the Round Table, and bade them sit still, that none of them remove. For ye shall see a strange and a marvellous adventure. Right so as they sat there came running in a white hart into the hall, and a white brachet next him, and thirty couple of black running hounds came after with a great cry, and the hart went about the Table Round as he went by other boards. The white brachet bit him by the buttock and pulled out a piece, wherethrough the hart leapt a great leap and overthrew a knight that sat at the board side; and therewith the knight arose and took up the brachet, and so went forth out of the hall, and took his horse and rode his way with the brachet. Right so anon came in a lady on a white palfrey, and cried aloud to King Arthur, Sir, suffer me not to have this despite, for the brachet was mine that the knight led away. I may not do therewith, said the king.
With this there came a knight riding all armed on a great horse, and took the lady away with him with force, and ever she cried and made great dole. When she was gone the king was glad, for she made such a noise. Nay, said Merlin, ye may not leave these adventures so lightly; for these adventures must be brought again or else it would be disworship to you and to your feast. I will, said the king, that all be done by your advice. Then, said Merlin, let call Sir Gawaine, for he must bring again the white hart. Also, sir, ye must let call Sir Tor, for he must bring again the brachet and the knight, or else slay him. Also let call King Pellinore, for he must bring again the lady and the knight, or else slay him. And these three knights shall do marvellous adventures or they come again. Then were they called all three as it rehearseth afore, and each of them took his charge, and armed them surely. But Sir Gawaine had the first request, and therefore we will begin at him.