A duchy in west central France, its capital by the same name was the capital of Poitou.
In Arthour and Merlin, we learn that Uther Pendragon acquired it from Harinan, Igerne’s (Igraine) first husband. The Alliterative Morte Arthure names it as part of Arthur’s empire.
Malory says that Lancelot owned it, and that he made Bleoberis the duke of Poitiers in return for Bleoberis’s support in the battles against King Arthur.
In Chrétien’s time, Poitiers was apparently known for its armor: Meliagrant’s helmet had been made there.