Rosalind Kerven on her search for King Arthur’s Celtic roots.

My editor was uncompromising: “We’d like you to do a retelling of King Arthur. But it must be absolutely authentic.”

Authentic? Images leapt into my mind - the Middle Ages, stone castles, turrets and tournaments, courtly love, damsels in distress and knights in shining armour. But as soon as I set out to research the book, all these preconceptions came crashing down.

King Arthur’s story is a legend - an imaginative traditional story, loosely based on historical fact. Over the centuries many authors have reworked it according to their whims. To be truly authentic, you must go back to the story’s historical roots.

The recognised storyline is based on Sir Thomas Malory’s lengthy Le Morte D’Arthur, published in 1485. As well as being packed with all the elements you would expect, it is also peppered with intriguing asides about how different things were in “King Arthur’s days”.

The trail leads backwards, through 13th and 12th-century French romances to the oldest surviving detailed account of Arthur’s reign: Geoffrey of Monmouth’s 1136 History of the Kings of Britain. This has quite a different flavour from Malory, with a rougher edge and much more emphasis on mysticism. Beyond this, fragmented 9th-century Welsh manuscripts contain tantalisingly brief and cryptic references to Arthur as an outstanding war hero. From these, historians and archaeologists have traced the “real” Arthur back even further, to the late 5th or early 6th century AD.

So artist Tudor Humphries and I found ourselves immersed in the Dark Ages, removed from the popular image of medieval Camelot. Arthur lived in the post-Roman era, when Britain was reverting to its native Celtic culture. His “castle” was most likely a wooden fortress, built on the site of a prehistoric hill fort. His followers were not the courtly knights of popular imagination, but fearless Celtic warriors.

Against this background, I interpreted the story from a fresh perspective. In the world of early Celtic myths and legends, a man’s reputation depended on the power of his personality and glory in battle, tempered by a strict code of honour. But many versions of King Arthur belie this. They tend to depict Arthur as an uncertain youth who, later in life, lurks impassively in the background as great events unfold around him. My task was to bring back the “true” Arthur as idolised in the earliest stories - invincible from the outset, charismatic and principled - a “great man’ until the end.

The women for whose love the legendary Celtic warriors risked their lives and kingdoms were not the insipid, fickle damsels portrayed in the Middle Ages. Instead, many move through the old stories as proud and confident protagonists. So I drew the three most important women from Malory’s cast and enlarged them into key players. I also gave more prominence to Celtic mysticism, emphasising beliefs in the power of magic and the “other world” of Avalon.

The Dark Age context provided the perfect framework in which to style the retelling. Although often presented as a novel, King Arthur was created in an largely illiterate age, and was originally recited aloud by travelling bards. They faced similar challenges to those of a children’s writer - having to hold a potentially restless audience’s attention by omitting waffle, limiting descriptions to minimalist poetic sketches, and making the story coherent and satisfying. Working the text in this “oral” way was liberating, and allowed me to fit the whole plot comfortably into a highly-illustrated book of limited length.

King Arthur is Britain’s greatest and most enduring traditional tale. It was a strangely haunting experience to find its true form and bring it alive again for a new generation.