Lady Bertilak was a French woman that had been imprisoned by King Claudas within Terre Deserte. She was imprisoned along with Lancelot du Lac and Prince Lionel until they heard of King Bors' invasion of Berry. The trio escaped but were chased by the curs holding them prisoner. King Arthur and his group, including Sir Bors, arrived and Bors had to make a choice; save the woman or save his brother, Lionel. He chose the chivalrous option and saved Lady Bertilak who wanted to repay him, but he refused her advances. Lionel cursed his brother for not choosing to save him. Lady Bertilak asked Sir Bors to vouch for her safety if she went with him, which the knight then kept for many years.