Bearing the same name as Uther Pendragon, this sounds as if it should have been a more important castle than Malory otherwise seems to indicate.
a noble man and a great enemy unto King Arthur.
Lancelot vanquished him and freed from his castle thirty of Arthur’s knights, including La Cote Male Taile (Brunor the Black), and forty ladies. Lancelot made La Cote Male Taile lord of Pendragon, following his marriage to Maledisant, with Sir Nerovens de Lile his lieutenant to have rule of the castle under him.
Neroneus of the Isle | The Legend of King Arthur
Le Morte Darthur | Sir Thomas Malory, 1469-1470