‘How far is it to the wall?’ Arrian asked.

‘Sixteen feet and seven inches,’ Rufus replied. ‘At least that’s what casting a plumb line told me last night. Give it that much cord and you hear the lead tinkle against the stone. Any less and it didn’t.’

‘Fascinating,’ Arrian said. ‘You know I had never really thought about how you judge the distance in a case like this.’

‘That’s the theory anyway, and I—’ Ferox had seen the stone coming from the right towards them and hauled Rufus under cover. The missile smashed into the earth rampart, flinging muck everywhere.

Rufus gulped. ‘Thank you,’ he said after a moment, and then peered back over the top, keeping lower this time. ‘They need to tie off the tower itself and replace the hauling parties with the ram’s crew. ‘I just hope that I’ve—’

‘It will be fine, I am sure, and if not, then that will also be fine,’ Arrian assured him. ‘There is no sense in worrying about things already done and which we cannot change.’

‘Don’t be a damned fool—’ Rufus snapped before he could stop himself. He realised that he had just insulted a senior officer.

Arrian smiled. ‘Well, I’ll try, but it would break the habits of a lifetime.’

‘What are they doing now?’ Ferox asked, to distract them both. Rufus explained how the ram’s crew had trained, swinging the heavy beam from a gantry rigged up in the workshop areas. Sixteen men operated the ram at any one time, and there were five teams to take over in turn. As he talked, his confidence grew, although his fingers still twitched nervously. In its final position the siege tower topped the fighting platforms of the towers on the wall by about the height of a man, and the archers were shooting much more often, making the most of the advantage.

‘They’re ready,’ Rufus said at last. They saw a man on the artillery platform stand at the open back of the tower and wave a red flag. Rufus seemed to be muttering a prayer or even a spell as he glanced back at the observation tower. Crispinus waited for what seemed an age, then raised his right hand and brought it down to hammer against the palm of his left hand. A cornicen sounded, the brazen rasp carrying over the noise of missiles. On the siege tower, the soldier with the flag bobbed it down to acknowledge the order, and Ferox and the others heard the shouted, ‘Begin!’

Rufus held his breath. In the tower, the sixteen men waited for the call and then pulled back as one and slammed forward. The ram was made from six beams, each seventy feet long and bound together all along their length. At the tip was the iron head, cast like the head of a horned ram, its face down as it charged. The tower creaked as the weight shifted.

There was a sharp crack as the ram struck the stone wall squarely. Rufus breathed out. Arrian smiled again, and patted him on the back.