'Bring it here!' Pacorus shouted.

The guard picked up the cushion, an amazed look on his face. He walked to the commander, bowed and handed it to him.

Pacorus stared, fascinated. The arrow had only penetrated two fingers' depth into the filling. With a gentle tug, he pulled it free. The barbed head was completely covered in fabric.

Silk that was hardly torn or damaged.

The Parthian goggled.

'Wrap half a dozen layers of that over a scutum,' Tarquinius pronounced, 'and you have an army that can withstand any arrow.'

New respect for the haruspex filled Pacorus' eyes.

'You saw Roman discipline at Carrhae before the cataphracts charged. Legionaries are the finest infantry in the world,' said Tarquinius. 'With silk on our shields, the Forgotten Legion will be unbeatable.'

'Those tribes outnumber us.'

'They do not stand a chance,' repeated Tarquinius.

'Why tell me this?'

'My friends and I have no wish to die. We were lucky to survive the last battle.' Tarquinius raised his eyebrows expressively. 'Facing those bows a second time . . .'

Pacorus was intrigued. Unknown to the Etruscan, his new command from Orodes was a double-edged sword. Historically the horse archers and cataphracts had been able to keep the steppe nomads at bay. But the war with Rome had depleted Parthia's border forces to dangerously low levels and there had been news recently of incursions deep into the empire. Facing marauding tribes with few bowmen of his own had been worrying Pacorus since leaving Seleucia.

The Parthian poured more wine.

'There's your caravan,' said Brennus, shielding his eyes from the sun.

Romulus grinned. Both of them had been impatiently scanning the horizon since Tarquinius' night visit to Pacorus.

Exactly twelve days had passed.

Dust billowed into hot air in the middle distance. It was never difficult to spot movement on the flat plain that had replaced the sand dunes. A long line of camels could just be made out, stretching back into the haze.

Pacorus spotted the animals too and bellowed for the column to halt. The drums beat further commands. Most soldiers had learned basic Parthian orders by now and obeyed promptly. Recognising that new troops would fight best the way they had been trained, the shrewd officer had already learned many Roman manoeuvres from Tarquinius. A day earlier, he had taken the step of arming all the prisoners again. Again, no one but the Etruscan knew why. Despite their initial enjoyment at marching unburdened, the legionaries were proud to carry javelins, swords and shields once more.

Responding to the calls, the cohorts fanned out in a defensive line, six across, three deep, with two protecting the baggage train at the rear. Everyone grounded weapons and scuta, taking sips of water as they waited. Lean and fit, the Roman soldiers had become used to marching in the heat, and exhaustion was no longer an issue. Deep in Parthian territory, few worried at what was approaching.

Some time passed. Gradually the train grew near enough to make out more details. There were about thirty single-humped animals, walking with a distinctive rolling motion. Heavy cloth panniers hung from the sides of each.

'Extraordinary beasts. They can go for days without water,' commented Tarquinius.

Romulus studied them closely as they drew nearer. At Carrhae, the camels had been too far away to see properly.

A party of fifty men accompanied the beasts of burden. Most looked like bodyguards, hired to protect the merchants and their goods. All wore long robes and head-dresses to protect against the sun and most carried a spear and bow. A few wore swords. They showed little signs of discipline. Several scouts rode nervously alongside, their job of reporting the Romans' presence done.

Tarquinius gave them a quick glance. 'Mixture of Indians, Greeks and Parthians. Enough protection against most bandits.'

'Half a century would take them out,' said Romulus.

'There'll be no need,' smiled Brennus. 'Look at them.'

The caravan came to a halt a short distance away and the dust began to settle. Camels roared loudly, glad of a rest.

It was obvious that the newcomers were nervous. Hands gripped weapons tightly, feet stamped on hot sand. Dark eyes shifted uneasily in sweaty faces. There was nothing the traders could do when faced with such overwhelming force. The plain was flat for miles on end.

'I suppose we 're not a common sight,' observed Romulus wryly.

Everyone laughed. Ten thousand legionaries in the middle of Parthia would seem bizarre to other travellers.

Eventually a short man in a grimy white robe began to approach them, his hands held high in a gesture of peace. Three guards followed with dragging feet. Halfway over to the legions, the figure stopped, waiting for a response.

Pacorus glanced at Tarquinius. 'Squad of ten men!' he barked. 'Form up and follow me!'

The Etruscan saluted crisply and led Brennus, Romulus, Felix and seven others to stand in line behind the Parthian. With the legionaries marching to his rear, Pacorus walked his horse slowly across the sand and halted twenty paces from the other party. Tarquinius shouted an order and the files re-formed, facing forwards, scuta at the ready.

The old man in the dirty robe leaned on a well-worn staff, surveying the approaching soldiers. Straggling white hair framed a shrewd face with a large hooked nose. His skin was a deep nut brown, the result of years in the sun. He seemed visibly relieved to find a Parthian in charge.

'Who are you?' demanded Pacorus. 'And where are you bound?'

'My name is Isaac,' replied the stranger swiftly. 'I am a merchant travelling to Syria via Seleucia.' He paused for a moment before daring to ask. 'Who might you be, Excellency?'

Pacorus chuckled. 'An officer of King Orodes' army.' He turned in the saddle, gesturing at the massed cohorts. 'And here are his latest recruits.'

Isaac's mouth opened and closed. 'They look like legionaries.'

'Old eyes do not deceive,' said Pacorus. 'Some months ago, we crushed a huge Roman army west of the capital. These are the survivors. The Forgotten Legion.'

The trader concealed his shock at the news of such an invasion. 'Good news indeed,' he smoothly replied. 'So it is safe to continue our journey?'

'Of course.' Pacorus bowed his head. 'After you have shared my hospitality. The king would wish it, I am sure.'

Isaac smiled, revealing decaying teeth. Not all Parthians could be trusted, but the offer had left no room for refusal.

'A day of rest would be welcome,' the Judaean said, turning and crying out in a high-pitched voice at the men by the camels.

Despite the fact that it was only midday, Pacorus called for camp to be built. Most soldiers complained bitterly about having to dig much earlier than normal. It was extremely hard labour to construct a rampart and ditch under the sun's full heat, but those in Romulus' cohort said little. They could tell the haruspex was plotting something.

A few hundred paces away, the camels had been tethered to pegs in the ground. Angry brays filled the air as they demanded food. Unfamiliar with the bizarre-looking creatures, the Romans stared with fascination. The camels' protuberant eyes, long lashes and wide lips gave an impression of real intelligence, but the humped animals also had vicious tempers, kicking and spitting at anyone who came too close.

Guards and traders had worked together to set up large roomy tents. Stacks of goods were carried inside the biggest. Making the most of the situation, Isaac was setting up full camp as well.

Romulus could hardly contain his excitement. Since Seleucia there had been little of interest apart from weapons training and Tarquinius' continuous lessons and the inquisitive young soldier was frequently bored. The long days of marching were tedious. The desert had been replaced by mountains, and yet more sandy wasteland had soon followed. There was almost no daily variation. The possibility of hearing stories from further east and seeing exotic goods was intoxicating.