Peredur appears in the list of Arthur’s knights in the Dream of Rhonabwy, Peredur appears as “Peredur son of Efrog” in the list of knights who accompany Gereint son of Erbin in the medieval Welsh story of the same name.
The romance of Peredur son of Efrog is found in two versions. The shorter version, that of the White Book of Rhydderch, contains material which approximately corresponds to the Perceval of Chrétien de Troyes from the beginning of the work up to Perceval’s return to Arthur’s court. The White Book follows this with otherwise unknown material which resembles in style French Arthurian romances. The Red Book of Hergest version has the same account, but continues it with material approximately corresponding to the remainder of Chrétien’s romance, the story of the Lady of the chessboard (found also in the Second Perceval Continuation and in the Didot-Perceval) followed by a unique conclusion to the tale.
Peredur is also used to represent Perceval in Y Seint Greal.
The name is explained in Y Seint Greal as par (‘spear') + dur (‘hard’).