Nennius’ Twelve Battles
Discover Nennius’ Twelve Battles of Arthur, from the River Glein to Mons Badonicus. Legendary tales and historical notes reveal Britain’s lost wars.
Introduction#
In Nennius’s Historia Brittonum (9th century), Arthur is not presented as a crowned king, but as dux bellorum — a “war-leader” or “duke of battle.” He emerges after the troubled reign of Vortigern, at a time when “the Saxons were thriving and increasing in multitudes in Britain.” Their leader is named as Octa, though it is uncertain whether he still held command during Arthur’s wars.
Arthur appears suddenly in the record, leading the British kings in combat and winning twelve victories against the Saxons at nine locations: the River Glein, the River Dubglas (four battles), the River Bassas, the Forest of Celidon, the Castle of Guinnion, the City of the Legion, the River Tribruit, Mount Agned (or Breguion), and finally the great victory at Badon Hill.
The geography of these battles is elusive. Celidon is often taken as the Caledonian Forest in Scotland, suggesting Arthur fought Pictish allies of the Saxons as well as the Saxons themselves. The City of the Legion is usually identified as either Chester (Deva) or Caerleon (Isca Augusta). Badon has been placed at Bath or Badbury Rings. Other sites — Glein, Dubglas, Bassas, Tribruit, Agned — remain uncertain, with candidates scattered across Britain from Cornwall to the north.
Some scholars argue that the wide spread of possible sites implies the battles were fought by different leaders, later attributed to Arthur as his fame grew. Others see it as evidence that Arthur commanded cavalry, allowing him to campaign across great distances. Another theory suggests that British warbands who fought in these places called themselves “Arthur’s Men,” confusing later writers into believing Arthur himself was present at every engagement.
Nennius gives no dates or timeframe, and it is possible that the Twelve Battles represent not a single campaign, but the span of a long career. Whether or not Arthur truly fought at each site, the list preserves the image of a leader who stood against the tide of invasion — a figure both elusive in history and enduring in legend.
Prologue: The Twelve Battles Remembered#
The Bard’s Tale#
Time and again the dragon-banner was unfurled, and twelve times Arthur met the foe. From the shadowed wood of Celidon to the high hill of Badon, he struck against Saxon, Scot, and Pict alike. At Badon, the Saxons gathered in their full might, yet Arthur rode with the image of the Virgin upon his shield. With a single charge he cut down hundreds, and the day was won. For a generation thereafter, the land knew peace, bought not with treaties, but with fire and steel.
The Scholar’s Note#
Our knowledge comes chiefly from Nennius’s Historia Brittonum (9th century), which lists Arthur’s twelve victories. The locations are obscure and debated, but the sequence portrays him as the defender of Britain against Saxons, Scots, and Picts. The final and greatest battle, Badon, is also mentioned by Gildas in the 6th century and by Bede in the 8th, though neither names Arthur. Later tradition firmly linked him to the victory, making it the centerpiece of the historical Arthur’s legacy.
Siege/standoff at the River Glein#
The Bard’s Tale#
Arthur’s forces waited along the banks of the River Glein, denying the Saxons any easy passage. For days the river became a line of steel, a barrier no foe could cross without challenge.f
The Scholar’s Note#
Nennius records the River Glein as Arthur’s first battle. While no formal “siege” is described, the river acted as a natural defensive barrier. Holding the banks delayed or disrupted Saxon movements, setting the stage for the ensuing clash.
Battle of the River Glein#
First battle
The Bard’s Tale#
By the banks of Glein, Arthur first drew his sword in Britain’s cause. The Saxons came in rafts and ranks, black sails blotting the dawn, but his war-band struck as they clambered ashore. Shield met spear in the shallows, and the river’s song was drowned by the clash of steel. The water ran red that day, and the invaders fled to their ships, leaving heaps of dead upon the strand. From this first triumph, the name of Arthur began to carry weight across the land.
The Scholar’s Note#
Nennius names the River Glein as Arthur’s first battle and victory, but the site remains disputed. Many identify it with the River Glen in Northumberland, near the coast where Saxon raiders might well have landed. Others argue for a more southerly location in Lincolnshire. What matters is less the geography than the symbolism: Glein stands as the starting point of Arthur’s recorded campaigns, where the legendary defender of Britain first rose to meet the Saxon threat, and the account emphasizes tactical control of natural barriers.
Siege/standoff at the River Dubglas#
The Bard’s Tale#
At the River Dubglas, four times Arthur’s men held the crossings against Saxon incursions. From the hills and meadows, Arthur’s men kept the crossings blocked, turning the river into a line no enemy could breach easily. Each time the enemy attempted to ford the river, they were met by spears and shields, the waters becoming a battleground in their own right.
The Scholar’s Note#
While described as separate engagements, the repeated Saxon attempts to cross suggest prolonged control of strategic river points. These repeated engagements highlight Arthur’s role as a skilled defender of key points.
Battle of the River Dubglas#
Second to fifth battles
The Bard’s Tale#
Four times Arthur fought upon the Dubglas, and four times he prevailed. The Saxons sought the crossings again and again, but each time they found Briton shields barring the way. On meadows trampled by hooves and churned with blood, the clang of arms rang out until even the river seemed weary of war. And still Arthur stood unbroken, until the name of Dubglas spread as a curse whispered in Saxon halls.
The Scholar’s Note#
Nennius places four consecutive battles “on the river Dubglas in the region of Linnuis.” The exact location is uncertain. Some scholars identify Linnuis with Lindsey in Lincolnshire, while others see echoes of northern territories. The multiple encounters suggest a drawn-out struggle for control of a contested frontier, perhaps a vital line of communication or access. Whether historical or symbolic, the repetition underlines Arthur’s persistence in meeting wave after wave of invasion along Britain’s vulnerable river borders.
Siege/standoff at the River Bassas#
The Bard’s Tale#
Along Bassas’ meadows, the Saxons attempted to bait Arthur into ambush. But the Britons watched from woods and hills, denying the enemy safe passage and controlling the flow of battle like a siege across a natural barrier.
The Scholar’s Note#
The engagement reinforces the pattern of Arthur using rivers as tactical defense, turning potential ambushes to his advantage. The standoff demonstrates the use of terrain to frustrate enemy movement.
Battle of the River Bassas#
Sixth battle
The Bard’s Tale#
At Bassas, the Saxons schemed to snare Arthur in ambush, but the snare snapped back upon them. Hidden in wood and hollow, his men struck as the foe waded midstream, weighted by water and shield. A roar went up, and the Britons fell upon them with spear and sword. When the moon rose, it shone upon reeds heavy with broken helms and upon Saxons strewn like driftwood along the banks.
The Scholar’s Note#
The location of the “river Bassas” has never been securely established. Some theories place it in the Thames basin, others in Wales or the North. The vagueness is typical of Nennius’s list, but the theme is telling: rivers recur as the stages of Arthur’s victories, reinforcing his role as defender at natural boundaries where invaders sought to penetrate the land. While the battle cannot be pinned to a map, it contributes to the image of Arthur as a leader who turned the land’s very geography into an ally.
Siege/standoff at the Forest of Celidon#
The Bard’s Tale#
In the shadowed forest of Celidon, Arthur’s men held the enemy at bay among the ancient oaks. The Picts and Saxons pressed, but the woods became a natural fortress, denying free passage.
The Scholar’s Note#
The “wood of Celidon” is often linked to the Caledonian Forest in southern Scotland. This suggests campaigns against northern tribes allied with Saxons, emphasizing terrain as a defensive tool.
Battle of the Forest of Celidon#
Seventh battle
The Bard’s Tale#
Deep in Celidon’s shadowed forest, where ancient oaks loomed like pillars of a cathedral, Arthur’s war-band met Pict and Saxon. The clash of axes and the cries of men mingled with the cries of ravens above. Yet the Britons turned the wildwood into fortress, striking from tree and thicket until their enemies fell in heaps among the roots.
The Scholar’s Note#
Nennius records a battle “in the wood of Celidon.” This is often identified with the Caledonian Forest in southern Scotland, placing Arthur’s campaigns deep in the north. The tale expands Arthur’s scope beyond Saxon foes, recalling broader traditions of conflict with Picts and Scots.
Siege at the Castellum Guinnion#
The Bard’s Tale#
Before Guinnion, Arthur’s host surrounded the fortress, preparing for assault. The enemy held the walls, but Arthur’s warriors waited patiently, cutting off escape and reinforcements.
The Scholar’s Note#
The castle of Guinnion is unidentified; some suggest Wales or southern Scotland. Nennius’ list implies Arthur’s ability to conduct sieges in addition to open-field battles.
Battle of the Castellum Guinnion#
Eighth battle
The Bard’s Tale#
At Guinnion’s fortress, Arthur bore upon his shield the image of the Holy Virgin. To his men it shone like a star, giving them courage, while to their foes it seemed a dreadful omen. With the cry of “Mary!” the Britons stormed the walls, and victory was theirs, as though heaven itself had fought beside them.
The Scholar’s Note#
The “castle of Guinnion” is uncertain in location, with candidates in both Wales and southern Scotland. More significant is the symbolism: this is the first overtly Christianized episode in the battle list. Whether reflecting a genuine cult image or a later gloss, it shows Arthur emerging not only as a war leader but as a champion of the faith.
Battle of the City of the Legion#
Ninth battle
The Bard’s Tale#
Arthur marched upon the City of the Legion, whose Roman walls had long defied assault. With fire at the gates and fury at the walls, he cast down its defenders, and the Saxons within were cut to pieces. From tower to street, the city rang with his triumph, and the eagle of Rome seemed once more to soar above Britain’s cause.
The Scholar’s Note#
The “City of the Legion” could be Chester (Deva) or Caerleon (Isca Augusta), both major Roman legionary bases. Though scholars disagree, the episode places Arthur not only on rivers and frontiers but also at fortified cities, centers of authority whose capture would resonate with both memory and legend.
Siege/standoff at the River Tribruit#
The Bard’s Tale#
At Tribruit, Arthur’s men controlled the river line. The Saxons waited, uncertain how to advance across the waters defended by Briton spears.
The Scholar’s Note#
The prolonged standoff reflects strategic control of terrain, and Nennius emphasizes the pattern of controlling river lines.
Battle of the River Tribruit#
Tenth battle
The Bard’s Tale#
On the banks of Tribruit, Arthur faced a host said to number three hundred. Heroes of Britain stood at his side, their blades ringing until the Saxon shield-wall splintered and fled. In later song it was told that monsters too were among the foe, and that on Tribruit’s meadows Arthur’s men battled not only flesh but nightmare.
The Scholar’s Note#
The river Tribruit, or Tryfrwyd, also appears in the Welsh poem Pa Gur. There, Arthur’s warriors face not only Saxons but otherworldly enemies such as dog-headed men. This blending of martial memory with myth underscores how Nennius’s list draws upon both history and heroic poetry, straddling the line between chronicle and legend.
Siege of Mount Agned#
The Bard’s Tale#
Arthur’s men ascended Agned Hill, positioning themselves to meet the enemy. From the high ground, the foe could not advance freely, trapped by elevation and British discipline.
The Scholar’s Note#
Mount Agned is obscure, sometimes linked to Edinburgh. Nennius’ account emphasizes the strategic advantage of high ground.
Battle of Mount Agned#
Eleventh battle
The Bard’s Tale#
Arthur climbed the slopes of Agned Hill to meet his foes. Long was the struggle upon the high ground, but the Britons would not yield. At last, with a great shout, they drove the Saxons tumbling down the slopes, and the hill was marked forever by his name.
The Scholar’s Note#
Mount Agned remains obscure. Geoffrey of Monmouth later calls it “Agnet” and associates it with Edinburgh (Din Eidyn). Whether a Scottish hill-fort or another contested site, the battle reflects Arthur’s continuing campaigns in the north, though its precise geography is as elusive as its history. The battle reflects typical medieval tactics of hill defense and is consistent with Nennius’ brief mention.
Siege of Mons Badonicus#
The Bard’s Tale#
At Badon Hill, Arthur’s men held the heights. The Saxons surged repeatedly, yet the Britons’ lines held firm, turning the hill into a fortress of courage.
The Scholar’s Note#
Mons Badonicus (Badon Hill) is the most famous of Nennius’ battles. While precise location and events are uncertain, all sources mark it as a decisive victory that halted Saxon expansion.
Battle of Mons Badonicus#
Twelfth battle
The Bard’s Tale#
Upon the heights of Mons Badonicus, the fate of Britain trembled. For three days the Saxons hurled themselves against Arthur’s shield-wall, and for three days they shattered and fell back. At dawn on the fourth day, Arthur rode at the front, the Virgin’s image gleaming upon his shield, and led his warriors in a thunderous charge.
The Saxon host advanced like a dark tide, banners snapping in the wind, yet the Britons stood fast, a living wall of courage and steel. Arthur’s sword flashed like lightning, his knights carved paths through the throng — some say Bedivere’s lance struck down ten in a single thrust, while Kay’s shield turned aside a charge of many. The ground shook with the fury of battle until, at last, the invaders broke. The hill lay carpeted with the fallen, and from that day peace fell upon the land, a peace bought with fire and valor.
The Scholar’s Note#
Mons Badonicus, or Badon Hill, is the most celebrated of Arthur’s battles. Gildas (6th century) records a decisive British victory here, though he does not name Arthur. Nennius (9th century) and later Geoffrey of Monmouth place him at its head, securing his fame. The date, location, and details remain debated — ranging from Bath to southern England — but the outcome is clear: a halt to Saxon expansion and a generation of peace. Later tradition embroidered the tale with feats of Arthur and his knights, cementing it as the climax of his martial legacy.
