It was like watching a flock of birds change direction. Entirely consumed by terror, the leading Republican cavalry wheeled and urged their horses away from the merciless javelins, which offered nothing but death. Panicked, shouting incoherently, they collided with the squadrons behind, which were dividing up in preparation to assault Caesar’s rear.

Sick with tension, Brutus held his breath. If there were solid, disciplined officers in the enemy’s ranks, this was the moment to pull back, regroup and then charge them on the flanks and rear. If that happened, all his preparations and Caesar’s hopes would be dashed, and the struggle lost.

But faced with a retreating wave of terrified and injured comrades, the astonished riders did what most men would do in the circumstances. They turned and fled. In an instant, the Republican cavalry attack had become a rout. Trailing a huge cloud of dust, the horsemen galloped away into the distance.

Raising his bloodied pilum in the air, Brutus cheered. His cry was echoed by two thousand exhilarated legionaries, but their task was not over, nor the battle won.

The enemy cavalry’s panic and cowardice completely exposed thousands of advancing archers and slingers, who were there to support the mounted attack. Wails of fear rose up as they saw their protective screen vanish like so much morning mist. Ready for this exact moment, Caesar’s regrouped cavalry and light infantry swept forward again, creating a bloody slaughter that scattered the terrified, lightly armed soldiers across the plain.

The way to Pompey’s left flank was wide open now, thought Brutus delightedly. Looking around, he saw that his men had realised the same thing. It was time to deliver a hammer blow of their own.

‘Come on,’ Brutus shouted, trotting forward. ‘Let’s show those fuckers what real soldiers can do!’

It was half a mile at least to the Republican lines, but Brutus’ men charged forward like hunting dogs let slip from the leash. As they ran, he was aware of the third line moving on his left side. Caesar was making his final play by committing all his troops to the fray. Its legionaries would provide a much-needed input of fresh energy to the two sections which had now been locked in battle for some time.

Brutus’ main worry now was Pompey’s response to his attack. Like Caesar, he had probably held back his third line, which meant that his own cohorts’ advantage could be swiftly dispelled by Republican reinforcements. All the more reason for speed, Brutus thought, pushing himself into a sprint. Wearing a transverse crested bronze helmet and mail shirt and carrying a heavy scutum, it was an exhausting effort. The sun had been beating down on the dry plain since dawn and was near its zenith now. The air was hot and still, difficult to breathe. Most men had not drunk for hours and every throat was parched. Yet no one held back.

It was at moments like this that victory could be achieved.

And Caesar had placed his trust in them.

An hour later, and Brutus knew that the day was theirs. In a wonderful stroke of luck for Caesar, Pompey had committed all three lines of his army against his opponent’s two. Presumably an effort to bolster his raw troops, the measured decision had left the Republican leader with no reserves to counter Brutus’ wheeling attack. In addition, his cavalry were scattered to the four winds, and his missile troops butchered. Brutus and his six cohorts had fallen on Pompey’s unsuspecting left flank like wolves on helpless sheep. Driving the soldiers in it sideways, they watched delightedly as the panic spread.

When Caesar’s third line had crashed against the Republican front a few moments later, the end was nigh. Brutus had to give the enemy legionaries credit – holding their ranks, they fought on, refusing to run. It was a different story with Pompey’s allies, however. When the fate of their cavalry was followed by these further setbacks, they turned tail and fled towards their camp. With renewed courage, Caesar’s legions had pressed home their attack on the Republican legions. Step by step, they advanced, pushing their increasingly demoralised enemies backwards.

Brutus grinned mercilessly. It always started at the rear, when men who could see that their comrades in front were losing, looked back. Armed with long staffs, optiones and other junior officers were positioned here to prevent any retreat without orders. Thinly spread out though, they had no chance of stopping men from flight when the panic reached a critical mass. Inevitably that was what happened. Preceded by their commander, Pompey’s shattered legions had deserted the field as a disorganised rabble. Reaching the supposed safety of their fortified camp a short while later, they had been horrified when Caesar’s men followed and placed them under siege. After a short, vicious encounter, the gates had been forced, requiring Pompey and his soldiers to go on the run again.

Urged on now by Caesar himself, the exhausted legionaries were in hot pursuit of their defeated enemies, who were to be denied rest, water and food. The victory, thought Brutus, would be nothing less than total. Once again, Caesar had stolen victory from the jaws of defeat, this time using one of the most inventive tactics in the history of warfare.

Swallowing the warm dregs from his leather water carrier, Brutus grinned.

All they needed was to capture Pompey, and the civil war was virtually over.

In the event, that was not to happen. Although twenty-four thousand soldiers were taken prisoner, with numerous high-ranking officers and senators among them, Pompey and many others made good their escape that night. Included in this number were Petreius, Afrianus and Labienus, Caesar’s former friend and ally on the Gaulish campaign.

Early the next day, Brutus stood on a nearby hill, studying the battlefield. Fabiola was by his side, silently aghast. While not as bloody as Alesia, the human cost of Pharsalus had been high: over six thousand Republican legionaries lay dead below them, while Caesar had lost more than twelve hundred. Uncounted numbers of Republican allied troops were strewn everywhere, worthless in death as they had been in life. Clouds of vultures, eagles and other birds of prey already filled the air overhead.

‘Will they all just rot?’ asked Fabiola, revolted at that thought.

‘No. Look,’ answered Brutus, pointing. Small groups of men could be seen stacking wood in rectangular piles all across the plain. ‘Funeral pyres,’ he said.

Fabiola closed her eyes, imagining the smell of burning flesh. ‘Is it over then?’

Brutus sighed heavily. ‘I’m afraid not, my love.’

‘But this . . .’ Fabiola pointed at the carnage below them. ‘Have enough men not died?’

‘The losses are terrible,’ he agreed. ‘Yet the Optimates will not give up this easily. Word has it that they will take ship for Africa, where the Republican cause is still strong.’

Fabiola nodded. About the only area where Caesar had suffered a setback so far was in the province of Africa. The year before, Curio, his former tribune, had made the foolish mistake of being lured away from the coast and into the barren hinterland. There he and his army were annihilated by the cavalry of the king of Numidia, a Republican ally. ‘That will require another campaign,’ she said, wishing the bloodshed were already over. When it was, she could reactivate her plans to take revenge upon Caesar. ‘Won’t it?’

‘Yes,’ Brutus replied simply. ‘But you can go back to Rome at any stage. I’ll make sure you have enough protection.’

Pleased by this, Fabiola kissed his cheek. ‘I’ll stay by you, my love,’ she said, still wary of the potential danger from Scaevola. ‘What of Pompey?’

Brutus frowned. ‘The scouts say he headed east to the Aegean coast, unlike the others. From there, my guess is that he will sail for Parthia, or Egypt.’ He saw her questioning look. ‘The man won’t just give up. He needs more support for his cause.’