Merlin (Welsh: Myrddin) is a legendary figure best known as an enchanter or wizard featured in Arthurian legend and medieval Welsh poetry. The standard depiction of the character first appears in Geoffrey of Monmouth's Historia Regum Britanniae, written c. 1136, and is based on an amalgamation of previous historical and legendary figures.
Geoffrey's rendering of the character was immediately popular, especially in Wales. Later writers expanded the account to produce a fuller image. Merlin's traditional biography casts him as a cambion: born of a mortal woman, sired by an incubus, the non-human from whom he inherits his supernatural powers and abilities. Merlin matures to an ascendant sagehood and engineers the birth of Arthur through magic and intrigue. Later authors have Merlin serve as the king's adviser and mentor to the knights until he is bewitched and forever sealed or killed by the Lady of the Lake. He is popularly said to be buried in the magical forest of Brocéliande.
When US PresidentJohn F. Kennedy was magically sent back in time to Cam'lod'n, he sought out Arthur. Athough Arthur was away fighting the Saxons, Kennedy came to Merlin's attention. Merlin agreed to help Kennedy return to his own time. After research and study, Merlin arrived at a solution. However, when he discovered Kennedy in sexual congress with Queen Guinevere, Merlin balked at helping Kennedy. He relented when Guinevere threatened to tell Arthur that Merlin had molested her, and so he sent Kennedy home.