The Winter King: the true story of the King Arthur drama

It’s a story of a grittier, darker Arthur – not the genial ‘once and future king’ of chivalric tradition, but a hardened warrior who is trying to unite the fractured Britannic kingdoms against a Saxon menace.

How to watch The Winter King

All 10 episodes of The Winter King are available to stream on ITVX in the UK from 21 December 2023.

In the US, The Winter King is available on subscription channel MGM+.

The Winter King plot – when is it set?

The Winter King is set in the fifth century AD, during the so-called ‘Dark Ages’ that followed the Romans’ withdrawal from Britain.

The story centres on Arthur Pendragon – an inspiring leader and peerless tactician, but no king-in-waiting – and would-be warrior Derfel Cadarn, whom Arthur saved from certain death as a child and later becomes one of his staunchest allies.

Uther Pendragon, Arthur’s father, sits on the throne as High King of Dumnonia (a kingdom approximately in Devon, though also including parts of modern Cornwall and Somerset).

Though powerful, Uther’s position in Caer Cadarn – aka Camelot in all but name, fictionally placed in the vicinity of Cadbury Castle – is quite precarious.

He is old and ailing, and yet is locked in fights against both rival British clans and the encroaching Saxons, who hold dominion over the ‘lost lands’ to the east and threaten to overrun all of Britain.

With Uther’s heir – the club-footed Mordred – but a newborn babe, the druid Merlin takes it upon himself to seek out Arthur to save the kingdom.

Uther would never deign to seek Arthur’s aid. In this telling, Arthur is his bastard son, and a man Uther despises.

Arthur returns to Dumnonia to find a land in chaos. Beyond the politics and factional rivalries, amid the threats of raids and invasion, is the undercurrent of religious upheaval, as the struggles between the old Celtic gods and the new religion of Christianity begin to make themselves known.

Amid this story is the aforementioned Derfel, who as a child was saved from a death pit (about as delightful as it sounds) by Arthur and placed in Merlin’s care, where he forged a close bond with the druidess Nimue – the future Lady of the Lake.

The Winter King cast: who’s who in Arthurian Britain?

Discover the major characters in The Winter King – and how they differ from their counterparts of Arthurian legend

Arthur (Iain De Caestecker)

Not King Arthur, just Arthur. Uther’s bastard son, exiled across the sea, urged home by Merlin as the Saxon threat to his father’s kingdom grows.

Derfel Cadarn (Stuart Campbell)

The narrator of Bernard Cornwell’s novels. In the show, Arthur rescues Derfel from bleeding to death on a spike, engendering a lifelong loyalty that will make him one of Arthur’s most stalwart captains.

Uther Pendragon (Eddie Marsan)

High King of all Dumnonia, respected for his prowess, but rarely respectable. Arthurian legends hold that Arthur was conceived when Merlin enchanted Uther to look like Duke Gorlais, husband to Igraine, Arthur’s mother. In most of the tales, Uther also marries Igraine, making Arthur a legitimate heir.

Nimue (Ellie James)

The druidess who, in Arthurian tradition, becomes the Lady of the Lake and bestows the sword Excalibur on Arthur. In The Winter King, she is an orphan taken in by Merlin because the gods speak to her.

Merlin (Nathaniel Martello-White)

Neither a gnarled wizard nor a crafty conjurer, the Merlin of The Winter King is much more of politician – though he boasts a connection to the pagan gods.

Morgan (Valene Kane)

Perhaps better-known in Arthurian tradition as Morgan le Fay, she is Arthur’s half-sister in Arthurian tradition, though in The Winter King she is both his full sister and another of Uther’s bastards. A student of Merlin, in many Arthurian stories she starts as Arthur’s ally and later becomes an enemy.

Guinevere (Jordan Alexandra)

In the romantic tales, Guinevere is Arthur’s great love – until she betrays him with Lancelot. In The Winter King, she is an ambitious political player.

Gundleus (Simon Merrells)

The rival king of Siluria with a love of slaughter, Gundleus is the source of many of Dumnonia’s problems.

Gorfydd (Aneirin Hughes)

King of Powys and ruthless long-time enemy of Uther and Dumnonia.

How historically accurate is The Winter King's King Arthur?

In The Winter King it is not King Arthur, just Arthur. He is Uther Pendragon's bastard son, exiled across the sea, urged home by Merlin as the Saxon threat to his father’s kingdom grows.

As for the question of a real King Arthur, all that is known with any certainty all, says historian John Matthews, "is that a man named Arthur, or Arturus, led a band of heroic warriors who spearheaded the resistance of Britons against the invading Saxons ... sometime in the fifth and sixth centuries AD".

Whether this man was a king – or indeed, real – is a topic of debate. Yet despite the man being something of a mystery, many of the events in the stories of King Arthur may well have happened – just to other people.

The sixth-century writer Gildas writes of the warlord called Ambrosius Aurelianus, described as being of Roman stock and whose battles against the Saxons included a triumph at Mount Badon, a victory often ascribed to King Arthur.

Geoffrey of Monmouth, the 12th-century writer whose Historia Regum Britanniae became a cornerstone for Arthur's enduring popularity in Britain, describes how the warrior king Cassivellaunus was betrayed by his treacherous nephew, Mandubracius, after failing to pay a tribute to Rome.

Switch Mandubracius for Mordred and we see another mirror to the legends of King Arthur.

As historian and archaeologist Miles Russell writes, there may have been five men who make up King Arthur.

Is The Winter King's Derfel Cadarn real?

The entirety of the The Winter King novel is told through the eyes of Derfel, an elderly monk recounting his time as one of Arthur’s most loyal warriors.

Just as there was a real Uhtred of Bebbanburg, so too Derfel has a very loose real-life counterpart – though perhaps not one his zealously Christian nemesis Bishop Sansum would recognise.

Though the Derfel of the novel cleaves to his adherence of the old gods, there is a historical Derfel considered a Christian saint.

Saint Derfel Gadarn (not Cadarn) was said to be one of seven warriors who survived King Arthur after the battle of Camlann, the clash in which Arthur was mortally wounded.

Following Arthur’s death, Derfel is said to have hung up his sword and entered religious life – which author Bernard Cornwell mirrors in The Warlord Chronicles by having Derfel tell his tale while scribing in a monastery.

The church dedicated to him – St Derfel’s in LLanderfel, Gwynedd – became a popular site of pilgrimage in the medieval period owing to its wooden carving of the saint.

Sadly, you can’t see this sculpture of Derfel today. Owing to a legend that said the effigy would one day burn down a forest, it was requisitioned by Thomas Cromwell during the Reformation.

He used it in the pyre of the unfortunately named Father John Forest, a priest who was burned alive for denying Henry VIII’s position as head of the Church of England.

Is The Winter King a true story?

In the entirety of Arthurian legend, there is just one event we can be sure of as being true, according to British folklore expert Ronald Hutton – the battle of Mount Badon.

We know this, he says, because it appears in a "near-contemporary text" a list of complaints written by the aforementioned Gildas. "The real problem is that we're still not certain if there was a historical Arthur actually linked to it and if he won it."

As for The Winter King – the story of the novel is simply another version of a legend.

Looking for something else to watch? Explore our full round-up of the best historical TV and film available to stream right now, or the new history TV and radio airing in the UK this month.