‘Where are you now?’

‘By our reckoning, almost at the point where the inner wall branches off from the main one.’

‘That is their citadel,’ Crispinus explained. ‘We did not want to get inside one wall and still be shut out from the other so have aimed for the join.’

Hadrian nodded encouragingly, his features shadowed in the dim lamplight inside the tunnel. ‘And how sure can you be of your reckoning?’ He waved his hand in front of Crispinus because he wanted the centurion on the spot to speak. ‘It must be hard to be precise.’

‘We are confident, my lord. We know the angles and the distance. But as anyone will tell you, always best to add a tenth to your target. Better to go too long than come up short.’

‘And better still not to waste time answering damned fool questions from nosy aristocrats, eh!’ Hadrian grinned. ‘You’re doing wonderfully. Keep it up.’

‘I am impressed,’ Hadrian assured Crispinus as they went on their way, heading for the western ramp. They were close enough to hear a sharper noise of metal striking stone after the heavier thump of each blow. ‘Everything is well in hand. I knew I was giving you a very tough nut to crack with only the barest minimum of resources, and yet here we are, on the brink of success. Ah, here is Ferox.’ Hadrian had requested the presence of the centurion, who was now trotting towards them.

‘Well met, Flavius Ferox – and well done!’

‘My lord.’

‘Ah, your usual garrulous self, I see. After all these years, you really ought to appear more Roman and forthcoming.’

‘Sir.’

‘Why did I want to see you?’ Hadrian asked.

‘As a reminder that some problems are insoluble, my lord,’ Crispinus suggested, ‘for some people never change.’

‘True. They have their uses, though. Tell me, have you seen any sign of the errant Domitius?’

‘Once or twice on the walls.’

‘Can you really be sure. Faces up there seem so small.’

‘It’s him, my lord.’

There was little left of the corpse suspended from the walls when Crispinus drew their attention to it.

‘Poor fellow,’ Hadrian said. ‘Wonder who he was?’

Crispinus dropped his voice even though the closest trooper was some way away. ‘We did wonder about your man.’

‘I doubt that it is him, but time will tell.’ Hadrian reined in. They were out of range of the walls, but still a couple of hundred paces from the tower. Looking from the side, it meant that they could see the ram strike. The sun was setting, casting a long shadow in front of the tower and showing the puffs of dust each time the ram’s head struck the wall. Artillery was shooting from both sides, the stones dark against the pale wall and bolts glinting when they caught the light.

The ram slammed into the wall again, and there was another puff of dust from the impact. A cloud shrouded the space between the tower and the wall, and drifted around the tower itself.