The ninth battle was fought in the City of the Legion.
Word from Owain Whitetooth reaches Eboracum that a force of Irish and Saxons have breached the walls of Deva Victrix, the City of the Legion. Arthur realizes that this puts his new claim to the title of High King to the test. He sends Titus Drustanus ahead of the army, relying on his ability to pass unnoticed among the Irish to scout out the area. They discover that the Irish follow Crimthann, an Uí Liatháin prince whose family once controlled colonies in Britannia Prima, before Cunedda — Owain’s father, Lot’s older brother, and Lugh Striking-Hand’s uncle — pushed them out, at Vortigernos’s invitation. He has made a deal with Ælle to split the island between them once Arthur has been defeated. Crimthann isn’t stupid enough to really believe it, of course — he expects Ælle to go back on his word — he just sees an opportunity to grab some loot and place himself in a better position to regain his kingdom when the Bretwalda does betray him.
As the army crosses the mountains, they come under attack from a band of Saxon raiders. They take one of them hostage, who tells them that he follows Æthelflæd, and that both she and Vorcunos are following the army closely.
The army rendezvous with Titus and Owain at a small village north of Deva Victrix, with command of the city’s aqueduct. Quintus Badiovirus leads his men through the aqueduct into the heart of the city, while Titus’s men position themselves in the fort’s fabricum to save Owain’s capacity to manufacture otherwise-lost pieces of Roman military equipment and siege engines, including Badiovirus’s new flame-thrower and polybolos. Meanwhile, Arthur moves into position on the parade grounds outside the fort, while Lugh and Peredur ride into the city to gather up the raiders and drive them towards Arthur. Caius Hectorius finds himself engaged with Cymen, Ælle’s son and commander of the Saxons here, in a desperate fight — until the other warbands finish their tasks and are able to join him in the fight at the fort’s gates. They slay Cymen in battle, and drive the Irish out of the city, recapturing it for Owain Whitetooth.
Lucius Drustanus arrives on behalf of his lord, Marcus Cunomorus, telling Arthur of the enormous horde that Ælle has assembled, and its drive across southern Britain towards the Severn, threatening to divide Dumnonia from the rest of the island. This puts Arthur in an awkward position; he admits to his knights that he’s been in communication with Gerontius, the leader of the rebels seeking to overthrow Cunomorus and replace him with a Dumnonian king. He leaves the decision to his knights, who agree that they can’t afford to take on another fight right now, so they must back Cunomorus.