From the time the Roman Empire collapsed in the fifth century, until the Norman Conquest of 1066, civilization fell apart in Britain, and the country endured an era of chaos and warfare known as the Dark Ages. Few written records have survived from this time; consequently, the fifth century, when Arthur and Merlin are said to have lived, is an historical period steeped in mystery. The records that do survive only provide a rough outline of events, and most contemporary figures went completely unrecorded. Although, like Arthur, Merlin is mentioned in a few surviving Dark Age manuscripts, he is only referenced in passing. The first author to provide any actual detail concerning Merlin’s life was the Welsh cleric Geoffrey of Monmouth who wrote in the 1130s. In his History of the British Kings Geoffrey introduces Merlin by saying that he first proved himself as a youth when a British king named Vortigern chose him as a sacrifice. According to Geoffrey, Vortigern was building a fort on a mountain in North Wales to protect his kingdom from the invading Anglo-Saxons, but each time the fort was close to completion the foundations mysteriously collapsed. Vortigern’s advisors suggest that to put things right a boy must be sacrificed, and victim they pick is the young Merlin. However, just as Merlin is about to die, he tells the king that the problems are being caused by two dragons that dwell in a pool, in a cave below the fort’s foundations. When the pool is discovered and the dragons released, Vortigern is so impressed by Merlin’s mystic knowledge that he makes him his chief advisor and offers him the new fort as his own. Although this story is obviously an imaginative legend, a Dark Age manuscript records a similar story which reveals an historical figure behind the Merlin myth.
Vortigern was certainly an historical figure: he is recorded by Dark Age writers as the ruler of much of Britain in the mid-fifth century. Around the year 830 one Dark Age chronicler refers to King Vortigern when recounting a similar legend to Geoffrey’s story of Merlin and the two dragons. In his History of the Britons the British monk Nennius wrote about a young man who saved himself being sacrificed by Vortigern by revealing that two dragons dwelt in a cave below the king’s fort. The story is almost word-for-word that told by Geoffrey; the only difference is that the youth is not called Merlin, but Ambrosius. As both accounts are virtually identical, could this Ambrosius have been the man upon whom the stories of Merlin were based?
The dragon story was obviously an invention; Ambrosius, however, was not. Like Vortigern, he was an historical figure mentioned by other Dark Age writers. Although he is not record as a wizard, Ambrosius is recorded as uniting Britain in the post-Roman period. The work of a sixth-century monk named Gildas (The Ruin and Conquest of Britain, written around the year 545) refers to Ambrosius as a Roman aristocrat who led the British forces in their war against the invading Anglo-Saxons shortly after Vortigern’s reign. Additionally, the English historian Bede (in his Ecclesiastical History of the English Nation, written in 731) says that Ambrosius’ family name was Aurelius. The Aurelius family was a powerful Roman dynasty descended from the second-century Roman emperor Marcus Aurelius, and archaeology has shown that when the Roman legions departed members of this family remained in Britain (see here). This Ambrosius Aurelius was therefore undoubtedly an historical figure, and the works of Geoffrey of Monmouth and Nennius taken together imply that Merlin was originally thought to be him.
Why, though, if Ambrosius was the historical figure behind the story of Arthur’s wise advisor, has he gone down in legend under the name Merlin? The answer seems to be that the name Merlin was actually a title. Many British warriors of the time adopted the battle names of animals. The monk Gildas, for example, refers to a number of British kings of his time by such titles as the Lion, the Hound and the Leopard. Even the name Arthur seems to have been a title coming from the old British word Arth, meaning Bear. The name Merlin appears to derive from the old British meaning “the Eagle”. (In fact, there is still a bird of prey called a merlin to this day.) A number of Dark Age poems are preserved as copies in a medieval manuscript known as The Red Book of Hergest, now in the Bodleian Library at Oxford University. One of these poems clearly demonstrates that Merlin was named after this bird: concerning a prediction Merlin is said to have made, it is entitled The Prophecy of the Eagle.