The Countess seems to have been a sovereign lady over Orofoise.
During the Saxon invasion of Britain, the Saxon king Aminaduc’s warriors were hard pressed by Arthur and the Knights of the Round Table. Aminaduc’s wife sent a Saxon giant to lay waste to Orofoise, hoping that Arthur’s knights would be drawn to the adventure and would be slain.
The Countess of Orofoise sent her sister to Arthur seeking help, Arthur took the opportunity to go to bed with the beautiful sister. He personally responded to the Countess’ need for aid and fought the giant.
The giant wore armor of impervious serpent hides, which must have caused Arthur a spot of trouble, but he succeeded to defeat the giant, and thereafter answered the Countess’ plea for justice and had the giant drowned in a river.
Source
Le Livre d’Artus | Early 13th century