Merlin (Welsh: Myrddin, Cornish: Merdhyn, Breton: Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a magician, with several other main roles. The familiar depiction of Merlin, based on an amalgamation of historical and legendary figures, was introduced by the 12th-century British pseudo-historical author Geoffrey of Monmouth and then built on by the French poet Robert de Boron and prose successors in the 13th century.
https://en.wikipedia.org/wiki/Merlin