In the Middle Dutch romance Walewein, a prince enchanted by his stepmother in the form of a fox.
He joined Gawain during Gawain’s quest for the Floating Chessboard. Roges could only return to human form if he saw King Wonder, his son, Gawain, and the maiden Ysabele all together in the same place. At the conclusion of the adventure, Gawain returned to Wonder’s court, the condition was met, and Roges became a man again.
Source
Roman van Walewein | Penninc and Pieter Vostaert, mid to late 13th century