Miraculously, Bassius alone remained standing, shield peppered with arrows. 'Aim short! Loose!' he screamed.

With a heave, Romulus and the men of the second two ranks swung forward, launching their pila in low curving arcs. They fell in a flurry of wood and metal, finding targets at last. From such a short distance, Roman javelins were also lethal. Horses fell screaming to the sand, throwing their riders. Dozens of warriors were hit, but the force of the charge was such that they were carried past to safety.

Another brutal volley scythed into the side of the cohort before Bassius had time to respond. And then the Parthians were gone, galloping off to attack another square. The noise of hooves died away, to be replaced by screams.

At least eighty men lay strewn across the hot sand.

Romulus gaped at the sight. Scores of soldiers had been killed outright by arrows which had passed through shield and chain mail, ripping into soft flesh beneath. Scuta lay pinned to prone bodies all around and a dense network of wooden shafts peppered the ground. So many had been injured that Romulus looked himself over in disbelief. He had not suffered so much as a scratch. Neither had his friends.

'They can do that all day,' Tarquinius said calmly.

His face grim, Brennus muttered and cursed.

Through clouds of dust, other cohorts were now being subjected to the same attacks as the archers swept around the Roman formations. For the moment, Bassius' depleted unit was an island of calm in the midst of chaos.

'Romulus! Get over here.'

Bassius was waving to him, his face knotted in pain. An arrow-riddled scutum hung from his left arm.

'What can I do, sir?'

'Cut out this damn thing!' The senior centurion swung out his wounded arm. A barbed head was protruding just below the elbow.

Romulus winced.

'Came clean through the shield.' Bassius shook his head. 'Thirty years of war, and I have never seen a bow as powerful.'

Romulus took the arrow in both hands and snapped it in two near the point. Bassius grunted in pain as the young soldier pulled the shaft backwards. The scutum fell from his grip and a fresh run of blood came from the two small wounds. Using a piece of cloth ripped from his tunic, Romulus bound the area tightly.

'Good lad,' said Bassius, picking up the shield again.

'You can't fight like that, sir.'

The centurion ignored him, moving back into position. 'Form square! There'll be another attack very soon.'

Romulus rejoined the ranks, wishing Bassius was in charge of more than a cohort. Officers like him were worth far more than Crassus.

A momentary calm fell on the battlefield as the Parthian archers withdrew, leaving mayhem behind.

'They've only gone to replenish their arrows.' Tarquinius watched the flocks of vultures gathering above. 'Crassus must seize this chance. The whole army should be in a continuous line, eight or ten ranks deep.' He indicated the battered units. 'Not like this. It's a massacre, not a battle.'

'How many casualties?' Crassus punched a fist into his palm. Unsettled, his horse skittered sideways, ears flattening.

'Still being counted, sir.' The junior tribune spoke with trepidation. 'But at least a tenth of every cohort.'

'A tenth of my army dead or wounded?'

'Yes, sir.'

'How many Parthians have been killed?'

'Not sure, sir.' The young officer was pale with fear. 'A few hundred, perhaps.'

'Get out of my sight,' Crassus spluttered. 'Before I have you executed!'

'It's hardly his fault, sir,' said Longinus, who had disobeyed orders yet again to come and remonstrate.

Hands twitching on his reins, Crassus glared at the legate. Nothing was being said about their argument before the battle started. Even he had realised what was more important now.

'What are your orders? The Parthians will attack again soon.'

'Send word to Publius,' cried Crassus abruptly, a wild look in his eyes. 'He must advance on the Parthian right with his cavalry and four cohorts of mercenaries. Create a diversion.'

Longinus paused. It was not what he would do.

'Is that clear?' The general's voice was suddenly calm. Too calm. Crassus glanced at the officer in charge of his guards.

The centurion laid a hand on his gladius.

Longinus saw the gesture and knew instantly what it meant. Any man who questioned Crassus' orders would now be killed. The legate saluted stiffly and paced over to the nearby scouts.

'When Publius has driven them back, we will charge the enemy's centre,' yelled Crassus after him.

Longinus did not reply. He was wondering what difference the ridiculous tactic would make. How could an army of infantry led by an arrogant madman beat a mobile enemy with no interest in fixed battle?

Romulus' cohort heard Crassus' orders when the messenger arrived moments later. Bucinae repeated the commands, common practice in battle to ensure they were passed on accurately. At once the Gaulish cavalry fanned out in front of Bassius' mercenaries, while the nearest cohort of Cappadocians moved to stand on their right. Two more came in to the rear, forming an arrow shape of cavalry, reinforced by a large square of foot soldiers behind.

Bassius grinned at his men. 'All right! This is a chance to show the whole army what we are capable of. Leave the yokes!'

'Take only water flasks,' said Tarquinius, stuffing something inside his tunic. 'We will not return to this position.'

His two friends quickly discarded all their equipment.

They did not have long to wait. Even Crassus knew that the time before another devastating Parthian attack was diminishing. The exhausted men could not withstand many like it.

Cavalry trumpets blared a staccato series of notes.

Publius assumed his position at the front of his cavalry. The noble 's short figure and brown hair were unremarkable, but his determined face and strong jaw drew attention. 'Advance!' he cried, pointing straight at the Parthians. 'For Rome and for Gaul!'

Urging their mounts forward, the tribesmen cheered loudly, kicking up sand and stones. Bassius and other centurions shouted at the mercenaries to follow.

'Let's show those bastards the sharp edge of our swords!'

There was a muted roar as tired bodies pushed into a trot behind the tough old officer. Despite his wound, Bassius seemed indestructible and his appetite for battle inspired everyone to follow.

'Ready pila!'

They ran with their arms cocked, heads bowed to avoid the clouds of dust from the horses' hooves. Romulus glanced at his friends from time to time. Having used both javelins in the first attack, Tarquinius slung his shield on his back, holding the double-headed axe firmly in both hands. Incredibly, he was smiling. Brennus' face was calm, his gaze focused.

Romulus' spirits rose and he laughed with the madness of it. The arena had been replaced by something even deadlier, but it no longer mattered. By his side were the two mentors who had become his family. Men he would die for and who would die for him. It was a good feeling. Romulus readied the pilum he had picked off the ground, ready to accept the gods' will.

With enormous effort, the cohort managed to keep up with the trotting horses. Marching on burning sand had been hard enough without having to run. Hot air scorched the soldiers' throats with every breath.

'Not much further,' panted Romulus when they had gone about five hundred paces.

The enemy's right flank was coming within the range of the Gauls' spears.

Tarquinius slowed down, his eyes narrowing.

Suddenly Publius ordered a full charge, and the infantry found themselves being left behind.

'Double time!' Bassius threw his arm forward. 'Let's take these fuckers!'

The men responded with superhuman effort to keep up. But instead of standing to meet the cavalry, the Parthians turned and fled.