Cato stood up and climbed on to the foredeck. He shaded his eyes as he squinted across the glinting surface of the river at the rider. There was no mistaking the powerful physique and the undeniable aura of command that the gladiator wore like a second skin. ‘You’re right.’

‘What I’d give to be in command of the bolt throwers now,’ Macro growled. ‘I’d have every one of them trained on that bastard.’

Cato nodded vaguely as he continued to stare at Ajax. Some of the crews on the island had realised the significance of the mounted figure and the first of the slender missiles whipped across the river towards him in a shallow arc. It missed, as did the second, and the third struck one of the small group of horsemen reined in behind their leader. Another flew on a true trajectory towards him, but Ajax flicked his reins and moved along the bank and the bolt disappeared into the long grass a short distance beyond where he had been just a moment before.

Macro had been noting the fall of shot. ‘That man has a charmed life.’

‘Not in the round,’ Cato replied. ‘He’s had his share of suffering.’

Macro looked at his friend sharply. ‘What? You pity him?’

‘Nothing so undignified. It’s just that had his fate been different, Ajax is a man we might have been pleased to call a friend, and proud to have fight at our side.’

Macro snorted. ‘And I might have been the fucking Emperor. There’s only one course through life, Cato. We are what we are, never what we might have been. As for what we will be, well,’ Macro spat over the side into the river, ‘that bastard will die. He has the blood of thousands on his hands. I only hope that it’s my blade that does the deed when his time comes. I defy the gods to try and stop me.’

For a man who was disposed towards superstition, this was strong stuff and Cato glanced at Macro in surprise. But before he could respond, there was another blast from the bucina and the sharp cracks of the bolt throwers died away as the artillery battery ceased shooting and trained their weapons round towards the flanks. At once the Arabs closed up and Ajax and his men took their shields up from their saddle horns and drew their swords.

‘Steer towards those men!’ Macro bellowed at the crewman on the tiller. ‘There!’ He thrust his arm towards the riverbank.

The crewman glanced round at the other boats on the left-hand side and shook his head. ‘I can’t, sir. We’d have to cut across their bows. We’d risk a collision.’

‘Just do it!’

‘No!’ Cato intervened. ‘Macro, we have to hold our course. If we hit another boat we’re going to lose men.’

Macro clenched his teeth and nodded, seething with frustration.