Merlin is a mythological figure prominently featured in the legend of King Arthur and best known as an enchanter or wizard. His usual depiction, based on an amalgamation of historical and legendary figures, was introduced by the 12th-century British author Geoffrey of Monmouth and the translator John of Cornwall. Geoffrey appears to have combined existing stories of Myrddin Wyllt, a North Brythonic prophet and madman with no connection to Arthur, with tales of the Romano-British war leader Ambrosius Aurelianus to form the composite figure called Merlinus Ambrosius . Geoffrey's rendering of the character became immediately popular, especially in Wales. Later writers in France and elsewhere expanded the account to produce a fuller image, creating one of the most important figures in the imagination and literature of the Middle Ages.
