The men of the Fourth Cohort instinctively closed ranks in an uneven ellipse around their wounded comrades. The enemy swarmed round them, hacking and chopping at the Roman shields in a rising frenzy as they sought to destroy the cohort before it could be reached by the relief column quick-marching towards them, but still far off. In the savage intimacy at the heart of the struggle Cato’s mind was wonderfully cleared of any thoughts but the need to take the life of his enemy and preserve his own. His shield and his sword felt like natural extensions to his body. Warding off blows with one then striking with the other, Cato moved with the deadly efficiency of a well-trained machine. At the same time, tiny sensory details, frozen images of the fight burned themselves into his memory: the acrid stink of mule sweat and the sweeter odour of blood; the churned-up ground about his muddy boots; the blood-spattered faces of friend and foe, feral and snarling; and the aching cold of the winter morning shuddering through his exhausted body.

The Durotriges whittled away the men of the cohort one by one. The wounded were drawn back into the centre while the dead were thrown out of the formation to stop their bodies being a hazard underfoot to their surviving comrades. And still the cohort lived on; the enemy dead piled up in front of their shields so that the Durotriges had to clamber over them to get at the legionaries. They presented perfect targets for the short swords as they balanced precariously on the uneven, yielding mass of dead and dying flesh, from which the terrified cries of the still living rang out above the thud of shields and sharp ring of metal on metal.

The intensity of the moment robbed Cato of any sense of the passage of time. He stood shoulder to shoulder with his centurion on one side, and young Figulus on the other. But Figulus was no longer Figulus the soft-featured lad perpetually fascinated by a world that was so very different from the squalid slum he had been born into in Lutetia. Figulus had been slashed above one eye; the torn flesh was hanging from his brow and half his face was dripping with blood. The gentle lips were drawn back in a savage snarl as he hissed and spat with the effort of battle. The months of training might never have taken place; as agony and rage took hold of him, he slashed and hacked with his short sword in a manner it had never been designed to be used. Even so, the Durotriges shrank back from him, awed by his terrible wrath. He drew back his blade for another lunge, and his elbow smashed into Cato’s nose. For an instant the optio’s head burst with white light before the pain rushed in.

‘Steady there!’ Cato shouted into his ear.