Not long after noon the track curved towards a small hillock. On its crest stood the raw dark earth of a recently erected rampart. A wooden palisade ran along the top of the earthworks with solid timber towers constructed above the two gates and at each corner of the fort. The distant detail of the structure was lost in the shimmering heat, but beyond the hill there was the glint of the Tamesis, looking cool and inviting to the eyes of sweating legionaries. Cato felt that he had not seen a more serene and peaceful view for months, but sight of the river brought the prospect of the coming battle sharply to mind. Soon enough those quiet waters would be stained with men’s blood and their corpses would lay strewn about under the harsh glare of the sun.

As the cohort approached, there was no sign of movement behind the rampart, almost as if the sentries had decided to find some shelter from the sun to enjoy an afternoon nap. Above the fort Cato could see tiny black dots slowly swirling: carrion birds of some kind, he decided. Apart from a few solitary swifts darting high and low, they were the only birds in the clear sky. When the cohort was in long arrow range of the fort and there was still no sign of life, Centurion Maximius halted his men and bellowed out an order for the scouts to mount and move ahead to investigate. With a soft thrumming of hoofs the scouts trotted forwards and started up the gentle incline towards the gatehouse.

‘Officers to the front!’

Cato ran forward, his harness jingling loudly as he passed by the silent ranks of each century. He joined the other officers breathing heavily and mopped the perspiration from his brow.

‘Something’s wrong,’ muttered Felix.

Maximius slowly turned towards him. ‘Really? Do you think so?’

Felix looked surprised. ‘Well, yes, sir. That or they have the worst sentries I’ve ever encountered. In which case someone’s in for a roasting.’

Maximius nodded. ‘Well, thank you for your concise appraisal of the situation. Most instructive . . . you idiot! Of course something’s wrong.’

Felix began to stammer something, and then shut his mouth and gazed down at his boots as he scraped one foot across the loose soil. The other centurions turned their gaze on the fort and silently watched the scouts ride up towards the entrance. One of the gates began to swing open slowly.

‘Sir!’

‘I see it, Antonius.’

A dark shape flitted out of the shadows under the gatehouse into the sunlight. A large dog, one of the hunting beasts the Batavians insisted on taking with them on campaign. It glanced quickly at the approaching horsemen and then turned and bolted down the slope in the opposite direction. For a moment the officers watched it run, sleek back bobbing up and down as it disappeared round the flank of the hill.