In Wirnt von Grafenberg’s Wigalois, a king of Syria.
He arrived at Arthur’s court at Caridoel (Cardueil) and offered Guinevere a magical belt, saying she could regard it as a present or else, if she preferred, he would come and fight for it. When she refused the gift, Joram challenged all of Arthur’s knights.
Through the powers of the belt, he defeated all of the Knights of the Round Table in turn. Gawain was the last to fall. Joram took Gawain prisoner and led him back to Syria. There, Gawain married Joram’s niece, Florie, and their union produced Wigalois.
Source
Wigalois | Wirnt von Grafenberg, early 13th century