Merlin, in giant form, helps build Stonehenge. British Library, Egerton 3028.

Myrddin Wyllt, Merlinus Caledonensis or Merlin Sylvestris (c. 540 - c. 584) is a historical figure in medieval Welsh legend, known as a prophet and a madman. According to lore he was a pagan bard driven mad after witnessing the horrors of war, who fled civilization to become a wild man of the wood in the 6th century. The disaster that brought him low was the death in battle of his lord Gwenddoleu, whom he served as bard. He prophesied his own murder on the very same day that he became a Christian.

He is the most important prototype for the modern composite image of Merlin, the wizard from Arthurian legend. That modern composite called Merlin began with Geoffrey of Monmouth. His book Prophetiae Merlini was intended to be a collection of the prophecies of the Welsh figure of Myrddin, whom he called Merlin. He included the Prophetiae in his more famous second work, the Historia Regum Britanniae. In this work, however, he constructed an account of Merlin's life that placed him in the time of Aurelius Ambrosius and King Arthur, decades before the lifetime of the original. Many other legends accumulated around this figure as shown in the illustration above which links him to the prehistoric world of Stonehenge (often mistakenly linked to the Druid cult active a thousand years later).

Merlin makes a comparably anachronistic intrusion into King Lear, III.ii.79-96 when the Fool says he "will speak a prophecy ere I go." He then launches a series of pradoxes about how unlikely good behavior is to come, concluding "This prohecy Merlin shall make, for I live before his time." This deliberate intermingling of epochs matches the intrusion of the Anglo-Saxon Edgar into Lear's pre-Roman reign. It also introduces another instance of insanity provoked by shock, reinforcing the multilayered plot and concertinaed chronology, similar to that of the mixed epochs and variants of madness and revenge in Hamlet, from Priam's Troy to Luther's Wittenberg.

Folio 30r of British Library, Egerton 3028, a manuscript of English chronicles including an abrevitated version the Brut by Wace. This illustration shows the construction of Stonehenge with the assistance of Merlin and is the oldest known illustration of Stonehenge. Author: Wace; Title: Roman de Brut, a verse epitome with continuation to Edward III; 2nd quarter 14th c.; Language: French. Picture and some data courtesy of the Yorck Project, under Creative Commons Attribution-Share-Alike License (Wikipedia).