Who was the chief wizard in Arthurian legend?

Merlin was the chief wizard, prophet, and adviser in Arthurian legend.

He is best known for guiding King Arthur, helping shape the king’s rise, and foretelling the fate of Britain. Depending on the version, Merlin advises Arthur’s father Uther Pendragon, assists in Arthur’s conception, oversees the young king’s education, and warns the court about dangers such as Mordred and the eventual fall of Arthur’s kingdom.

The literary Merlin was developed in the 12th century by Geoffrey of Monmouth. Geoffrey appears to have combined elements of the Welsh prophetic figure Myrddin Wyllt with Ambrosius, or Emrys, a legendary British leader. Later French romances expanded Merlin into the familiar magician and counselor of Arthurian tradition.

Merlin is sometimes confused with Nimue, also called Viviane or the Lady of the Lake. Nimue is generally portrayed as a magical woman who becomes Merlin’s student or beloved and, in several versions, traps or seals him away. Morgan le Fay is another powerful enchantress, but she is usually Arthur’s half-sister and rival rather than his chief wizard. Gandalf belongs to J. R. R. Tolkien’s Middle-earth, not Arthurian legend.