'Merely offering advice.'

'Insubordination!' Crassus cried. The black cloak he had donned that morning clung to his back, soaked in sweat. The legionaries on guard nearby eyed it uneasily. Black was the colour of death. 'Get into position, Legate, before I have you whipped.'

Longinus' jaw clenched. Few people would dare speak to a senior officer in such a manner. 'You are making a big mistake, sir,' he said insolently. The general needed him too much to follow through on the threat. 'Solid lines would be best.'

Crassus glanced at the others. 'Anyone care to agree?'

There was silence. His subordinates had been well picked.

'Consider your career finished,' said Crassus. 'If you survive the battle!'

'See what the Senate says about this back in Rome. They still have some power.' Longinus snorted with contempt and rode away, swallowing his anger. Crassus' arrogance would not stop them smashing the Parthians. He would sort out his problems with the general later. Longinus tried to put the bull's heart, the reversed eagle standard and the black cloak out of his mind.

'What are you all waiting for?' Spittle flew from Crassus' lips. 'Get out of my sight!'

The legates hastened to obey.

There was a battle to win.

Chapter XXIV: Publius and Surena

It took nearly half the afternoon for every legion to reach the plain. The desert horsemen sat in the shimmering haze, waiting patiently. Drums and bells kept up a relentless din. The outlandish sound was mindful of wild animals' roars intermingled with the sound of thunder.

It was terrifying.

Having waited the longest, the mercenaries were worst affected by the melting temperatures. Few had any water left and again men began to collapse from dehydration and heat exhaustion. The stronger soldiers did what they could for their comrades before battle commenced. Bassius stalked up and down, cajoling and threatening by turn. His sheer drive helped rally spirits that had fallen to a new low.

With Crassus' army finally in place, a staccato series of notes sounded from the bucinae. The waiting was over.

'You heard!' screamed the centurions. 'Get into position!'

Following routines that had been practised many times, the legions fanned out across the plain in a massive four-sided formation. Simultaneously each cohort formed into another hollow square, three men deep, forty in length and breadth. A hundred paces separated each from its neighbours in front and behind. Crassus, his officers and two veteran cohorts took their position in the empty middle along with the baggage train while the Gaulish and Iberian cavalry moved to sit on the wings. It was a most unusual formation for the start of a battle.

'What is he doing?' Romulus frowned. It was clear what would happen as soon as the attack began.

'Crassus thinks we might be completely outflanked,' said Brennus. 'This prevents it.'

'But not much else,' added Romulus, imagining how the Parthians would respond.

'He is a fool!' Tarquinius peered round angrily. 'Those archers will simply ride between the cohorts and pick us off with ease.'

It was unsettling that they could all see what would happen but Crassus could not. Any respect for authority Romulus had left was disappearing fast.

The Parthian leader was still in no hurry to attack. He waited until the Roman army had stopped manoeuvring.

At an unseen signal, the drums began pounding a heavy, rhythmic beat, different from before. The bells also changed tempo, their volume making even speech impossible. The noise went on and on, intimidating with its sheer energy. Exhausted by sunstroke and the incredible temperature, the dazed soldiers could only stare at the enemy, unsure what to do.

Suddenly, the clamour stopped.

A large group of horsemen in the Parthian centre separated from the rest. Slowly they moved forward to within a few hundred paces of the Roman front ranks, halting in unison.

Romulus peered into the haze. 'Who are they?'

'The cataphracts.' There was respect in Tarquinius' voice. 'Their elite heavy cavalry.'

'Long spears like Greek hoplites carry would soon sort them out,' said Romulus fiercely. 'If we had any.'

'Or a defensive ditch,' added the Gaul.

Tarquinius nodded approvingly.

The weary Romans stared miserably at the enemy, unable to do more than bake in the intense heat. It was almost a relief when the instruments started up again. With a flourish, the Parthian riders whipped off their cloaks, revealing chain mail from neck to mid-thigh. In each soldier's right hand was a heavy lance. The horses were also covered in armour, creating an immense wall of metal. Sunlight bounced off thousands of iron rings, reflecting towards the Romans in waves of blinding light.

Crassus' soldiers found it impossible to look directly at the cataphracts and the dazzling light wasn't the only reason. Fear was creeping into men's hearts.

'Amazing.' Tarquinius pointed excitedly. 'The andabatae in the arena were a mockery of the real thing.'

Romulus had only heard of the mounted gladiators who wore helmets with no eyeholes.

'Roman savages,' said the Gaul. 'Sending blind men into the arena to fight.'

'These riders are a different proposition,' pronounced the Etruscan.

Romulus was amazed by the mail rippling down the horses' flanks. He had never seen anything like it.

The cataphracts waited, maximising their terrifying effect. The drums kept up their dreadful din, deepening the sense of impending doom. Mercenaries and legionaries shifted uneasily from foot to foot. The unease in Crassus' army was becoming palpable, spreading to every man. Normally it was the Romans who scared their enemies by standing in silence before battle.

'Might have a decent fight today.' Brennus hefted his spear impatiently, eager to end their wait. 'Those bastards actually look dangerous.'

Tarquinius smiled humourlessly.

Wishing the battle would just start, Romulus checked his sword was loose in its scabbard, his pilum head securely attached to the shaft. Stay calm, he thought.

For what seemed an eternity, the two armies faced each other, soaking up the intense heat. The tension was unbearable.

And then the noise stopped. Immediately the horse archers moved forward while the heavy cavalry remained where they were.

'Prepare for an enemy charge,' ordered Bassius. 'Close order!'

The mercenaries had been well trained. Quickly the men readied their pila and spears and moved closer, standing shoulder to shoulder. Like tiny cogs in a big machine, thousands of soldiers across the battlefield did the same. Their shields overlapping, the formations presented the Parthians with dozens of armoured squares.

The enemy urged their mounts to a trot, followed by a gallop. The earth shook with the thunder of hooves and Romulus felt his stomach clench. The previous day's attacks would be as nothing compared to this.

Just as Tarquinius had predicted, the horsemen split smoothly into columns, aiming at gaps between the cohorts. Fear grew palpable in the ranks, men sweated heavily and hands grew clammy on javelin shafts. Behind him Romulus heard a man vomiting. He ignored the sound, lifting his scutum higher, squinting at the approaching riders.

Battle was about to commence.

The Parthians rode closer and closer. Soon they could see horses' nostrils flaring, the archers' faces tense as they drew back bowstrings.

Romulus' remaining pilum felt burning hot.

'Ready javelins!' There was no trace of fear in Bassius' voice. 'Wait till my command!'

Every man's right arm went back, ready for the order to release.

Before it could come, the Parthians fired a volley. It was from much closer range than the day before. Until that moment, the mercenaries had no idea just how powerful the enemy's composite bows were. Waves of arrows swept through the air, punching through Roman scuta like paper. The front rank dissolved, cut down to a man.