Romulus admired Caesar’s tactics, which caused instant panic in the Egyptian ranks. So there was a connection between them? He watched the fire spread in a kind of daze.

‘No,’ hissed Tarquinius. ‘Not like that.’

‘What’s wrong?’

‘If it moves down here, those will burn.’ The haruspex pointed at the large warehouses nearby.

Romulus did not understand.

‘That’s the library,’ said Tarquinius, his face twisted in anguish. ‘The ancient books in there are totally irreplaceable.’

Horrified, Romulus turned back. Already a quarter of the Egyptian ships were on fire, and the blaze was spreading fast. It was easy to see how the library might burn. Yet there was nothing they could do.

Tarquinius studied the conflagration for a few heartbeats and then his eyes opened wide with grief and awe. His faint hope that the Etruscan civilisation would see a new ascendancy was a false one. When the civil war was over, Rome would grow bigger and even more powerful, suffering nothing else to grow in its shadow. And Caesar would play a major role in beginning this process. He sighed, thinking that was all there was to see. But as ever, there was more. It was now he must tell Romulus, before it was too late.

Romulus was getting anxious. It was time to go. ‘Come on,’ he cried.

‘You asked why I left Italy in a hurry,’ the haruspex said suddenly.

‘Gods above,’ muttered Romulus. First the revelation about Caesar, then this. ‘Don’t tell me now. It can wait.’

‘No, it can’t,’ Tarquinius replied with a real sense of urgency. ‘I killed Rufus Caelius.’

‘What?’ Romulus spun around to look at the haruspex.

‘The nobleman outside the Lupanar.’

All the background noise died away as Romulus struggled to take in the impossible. ‘You? How . . . ?’ His voice trailed away.

‘It was me,’ Tarquinius hissed. ‘I was there, sitting near the doorway. Waiting for him.’

Romulus’ eyes widened with shock. There had been a small hooded and cloaked figure by the brothel. At the time, he had presumed it was a leper or a beggar.

‘But when Caelius came out,’ Tarquinius went on, ‘you picked a fight with him. I held back for a moment, but the breeze told me that I had to act fast. So I stabbed him.’

Romulus could not even speak. His hunch had been correct all along: the crack on the head he had delivered had not killed Caelius. Instead, Tarquinius had delivered the fatal blow. Confusion mixed with rage and Romulus’ mind reeled with the enormity of it. He and Brennus need not have fled Italy at all. ‘Why?’ he shouted. ‘Tell me why.’

‘Caelius murdered the man who taught me haruspicy. Olenus, my mentor.’

Romulus wasn’t listening. ‘You ruined my life that night,’ he retorted furiously. ‘And what about Brennus? Have you thought about that?’

Tarquinius did not reply. His dark eyes were full of sorrow.

‘Making prophecies is one thing,’ Romulus went on, outraged now. ‘Men can choose to believe or disbelieve what you say. But committing murder and letting an innocent man take the blame, that’s directly interfering with someone’s life. Mithras above! Did you have any idea of the effect you might have?’

‘Of course,’ replied Tarquinius quietly.

‘Then why did you do it?’ Romulus screamed. ‘I might have earned the rudis by now, and found my family. And Brennus would be alive, damn you!’

‘I’m sorry,’ faltered Tarquinius. Real sadness filled his face.

‘That’s not nearly enough.’

‘I should have told you long ago.’

‘Why didn’t you then?’ Romulus shot back bitterly.

‘How could I?’ Tarquinius replied. ‘Would you have kept as a friend the man responsible for all your troubles?’

There was no answer to that.

And then the gods turned their faces away.

The heavy tramp of men marching in unison came from behind them. It was very close. Sprinting to the corner, Romulus risked a look around it. The street down which they had come was entirely filled with approaching Egyptian troops. He spat a curse. They were marching to the aid of their comrades, or to attack the triremes. In the process, the soldiers had unknowingly blocked off their escape route.

They had two choices: to flee over the bridge and along the Heptastadion and risk being completely trapped, or to take their chances along the waterfront. Find a small alleyway to hide in until the battle had passed.

Tarquinius materialised at his shoulder.

Romulus clenched his jaw until it hurt. He wanted to throttle the haruspex, but this was no time to continue the feud. ‘What shall we do?’

‘Head for the island,’ Tarquinius replied. ‘We’ll be safe there until dawn.’

Shedding their cloaks, they turned and ran for the Heptastadion, some two hundred paces away.

Shouts rose from the triremes as they were spotted. Although they were illuminated against the light from the huge conflagration, Romulus was confident that they were beyond javelin range.

They sprinted on.

More cries rose from the Egyptian soldiers who had just reached the quayside.

Romulus glanced over his shoulder and could see some of them pointing in their direction.

‘Don’t stop,’ yelled Tarquinius. ‘They’ve got more to worry about than us.’

One hundred paces.

Romulus began to think that they would make it.

Then he saw the sentry picket: a squad of ten Roman legionaries standing on the edge of the Heptastadion, their attention focused on the heavy fighting. He glanced over himself. Caesar’s cohorts had smashed through the Egyptian lines and were pounding along the dock towards their triremes. The sentries cheered at the sight.

Mithras and Jupiter, Romulus thought frantically, let us pass unseen.

Tarquinius’ gaze rose to the heavens. His eyes widened at what he saw.

Fifty paces.

The gravel crunched beneath their caligae.

Thirty paces.

One of the legionaries half turned, muttering something in a comrade’s ear.

He saw them.

Twenty paces.

Now they were well within range of the sentries’ javelins; things happened very fast. A single pilum hummed through the air towards them, but landed harmlessly in the dirt. Another five followed, also falling short. The next four, thrown by men eager to bring down potential enemies, flew too long.

A pair per man, thought Romulus. Ten left. Still too many. He cringed inwardly, knowing that the best shots always held on to their pila until the last moment. At this range, the legionaries could hardly miss. And that was before drawing their gladii and charging them down. They could not make it.

Tarquinius realised the same thing. ‘Stop, you fools,’ he shouted in Latin. ‘We’re Romans.’ He slowed to a stop and raised his hands in the air.

Quickly Romulus did the same.

Remarkably, no more pila were launched. Instead, the sentries ran over, shields and swords at the ready. In the lead was a middle-aged optio. Within a few heartbeats they were surrounded by a ring of scuta, the sharp points of gladii poking between them. Hard, unshaven faces suspiciously studied the two friends.

‘Deserters?’ snarled the optio, looking at Romulus’ rusty chain mail and Tarquinius’ leather-bordered skirt. ‘Explain yourselves, fast.’

‘We work for a bestiarius, sir,’ Romulus explained smoothly. ‘Just got to Alexandria today, after being in the far south for months.’

‘Why are you creeping round like spies then?’ he demanded.

‘Our boss sent us in to check out the situation. We’re the only ones who can handle ourselves, see,’ replied Romulus with a knowing look. ‘But we got trapped by the fighting.’

The optio rubbed his chin for a moment. Romulus’ explanation wasn’t unreasonable. ‘And your weapons?’ he barked. ‘They’re Roman style, except for that thing.’ He pointed curiously at Tarquinius’ double-headed axe. ‘How come?’