Merlin (Robert de Boron poem)
Merlin is a partially lost French epic poem written by Robert de Boron in Old French and dating from around the end of the 12th century to the beginning of the 13th century. The author reworked Geoffrey of Monmouth's material on the legendary Merlin, emphasizing Merlin's power of prophesy and linking him to the Holy Grail.
Source: Wikipedia — Merlin (Robert de Boron poem) (CC BY-SA 4.0)