White stags feature in a number of Arthurian tales.
It was said that whoever hunted one down could kiss the loveliest girl in Arthur's court.
One was chased by Sagremor in Rigomer,
while another was hunted in the Forest of Adventure in Erec.
Floriant pursued one which brought him to the castle of his foster-mother,
Morgan Le Fay and, in the Didot Perceval,
Perceval cut off the head of a white stag.
The white stag may originally have featured in stories of a pagan,
mythical nature and these tales may have some connection with the Celtic stag cult.
The above text is from:
"The Encyclopædia of Arthurian Legends"
by Ronan Coghlan
publisher: BCA 1991