In the event, the expected clash with the Scythians did not occur. Realising perhaps that the response to their attack would be rapid and ruthless, the nomadic warriors had pulled back from where they had been spotted by the Parthian rider. Pacorus’ order for the men to carry enough supplies for several days turned out to be a fortunate one, as the legionaries marched fruitlessly after an enemy which had the advantage of being many miles away at the start of their pursuit. The exercise proved to be nothing more than an extended training march in winter conditions. Naturally, the soldiers were not pleased by this, but they had to obey.

After three days, with his men’s food running low, the Parthian commander was forced to call a halt. But he was determined not to give up. Upon their return to the fort, six cohorts were immediately provided with enough rations for a month and sent out again. Much of the winter passed in this fashion: searching an empty, frozen landscape for a wraithlike enemy. There were occasional skirmishes with the Scythians, but nothing decisive.

Like all the others, Romulus and Brennus took part in the sorties, marching alongside Aemilius and his men. Forced to join a contubernium, they had achieved grudging acceptance from the six legionaries with whom they lived, slept and ate every day. Yet there was no friendship and the other men in the century shunned them entirely. It was no better amongst the rest of the cohorts. Like Romulus and Brennus, Caius had fully recovered from his wound, and he was ceaseless in his efforts to foment bad feeling against the two friends. No one made direct attacks on them, but the threat was always there. They could not leave each other’s company, even to visit the latrines or baths.

It was an extremely wearing existence, and Romulus grew heartily sick of it. He and Brennus could not fight the entire legion. Desertion was their one option, although there was virtually nowhere to go. Well over a thousand miles of barren wilderness lay between the fort and the city of Seleucia in the west. It was hundreds more beyond that to Roman territory. To the north and east were unknown areas, populated by savage tribes like the Sogdians and Scythians. The land of Serica, where silk came from, lay even further eastwards, but he did not know where. Romulus had a single idea: to head south, through the kingdom of the Bactrians. Occasionally some of the Parthian warriors mentioned a great city called Barbaricum, where a mighty river met the sea. Romulus had seen it once on the Periplus, Tarquinius’ ancient, annotated map. He knew that Barbaricum was a bustling trade centre, where precious items such as spices, silk, jewels and ivory were bought and sold. From it, ships apparently sailed to Egypt, carrying goods that were worth a king’s ransom in Italy and Greece.

But Romulus had no idea how to reach it: the only possible route home.

And he would not leave without Tarquinius. Neither would Brennus. There was still no sign of the haruspex anyway. He was alive, yet, as before, he was kept under close guard in Pacorus’ quarters. Any attempt to free him would doubtless end in disaster, and so the pair watched, waited and endured for many cold months. All they could do was pray to the gods.

Spring arrived, and the six cohorts which were out on patrol surprised the Scythians in their camp. Utilising the dusk for an unusually timed attack, Vahram led his men to a stunning victory. Almost the entire force of raiders was annihilated in one short, brutal encounter. With little threat remaining, the primus pilus hurried back to the fort the next day. He was doing everything in his power to regain Pacorus’ approval. A pair of riders was sent on in advance to relay the good news.

When they returned, Pacorus was waiting at the fort’s main entrance with a party of his warriors. He called Vahram to his side and exchanged a few words with him before indicating that the legionaries should enter. As the ranks of the First Cohort began passing by, the commander dipped his head in acknowledgement. He seemed genuinely pleased by their victory.

Anger filled Romulus at the sight of the swarthy Parthian in his richly cut cloak, the picture of arrogant superiority. He longed to plunge his javelin into his chest, but of course he wouldn’t: he might gain his vengeance, but Tarquinius would still be a prisoner. The young soldier dared not act. He and Brennus had been fortunate to escape with their lives and avoid the commander since. He hoped that Pacorus had forgotten them for now. With Mithras’ blessing, it would stay that way. All the two friends could do was keep their heads down.

The First Cohort came to an abrupt halt and Romulus almost walked into the soldier ahead of him. Confused, men stood on tiptoe to see what was happening. A loud commotion came from the front. Angry shouts were met by a low, insistent voice which held one’s attention.

Recognition tickled the edges of Romulus’ memory.

Taller than nearly everyone, Brennus raised a hand to his eyes.

‘See anything?’ asked Romulus.

‘No,’ came the annoyed reply.

‘What’s going on?’ snarled Pacorus impatiently at the nearest centurion. ‘Move on!’

The officer scurried to obey, using liberal strokes of his vine cane on his men, but no one would budge.

A stooped figure wrapped in a heavy blanket emerged from the gateway. Shuffling rather than walking, it limped towards Pacorus. Superstitious gasps rose from the soldiers as they saw who it was.

Positioned on the outside of the rank, Romulus could see more than the Gaul. Sadness and euphoria filled him at the same time.

All the colour drained from Brennus’ face. ‘Is it . . . ?’ he began.

‘Yes,’ answered Romulus simply.

They had not seen him for months, but only one person in the camp had the ability to cause such confusion.

Angry that his order had not been obeyed, Pacorus snapped out another. Two of his men ran to stand before the figure, challenging it first in Parthian and then in bad Latin. There was no answer.

Another command rang out and one warrior stepped forward, roughly pulling away the blanket from the newcomer’s head. Obviously weak, he tottered backwards and nearly fell. Somehow he regained his balance and stepped forward. The Parthians blocked the move at once, but the man stood proudly, staring at Pacorus across their outstretched arms.

As Tarquinius’ face was revealed to those nearby, Romulus bit back the cry of horror that sprang to his lips. The haruspex had aged ten years. There were grey streaks in his long blond hair and new worry lines furrowed his entire face, giving him the appearance of an old man. The blanket had slipped away from his now bony shoulders, exposing his flesh, which was beaten and badly bruised. But the worst thing of all was the red, recently healed burn on Tarquinius’ left cheek. It was the shape of a knife blade.

‘They’ve tortured him,’ hissed Romulus, moving out of rank.

The Gaul’s great hand gripped his right arm, stopping him.

Romulus’ protest died away. ‘Each man’s fate is his own’ was one of the haruspex’ staple sayings. It was not his place to intervene. And Tarquinius had engineered this situation.

‘You!’ said Pacorus with a sneer. ‘Come to see what my troops have done without you?’

His warriors laughed.

Tarquinius licked his dry, cracked lips and Romulus’ heart ached.

‘Enough!’ barked the commander. ‘Move on,’ he shouted at the centurions.

‘Hold.’ Tarquinius’ voice was not loud, but every man heard what he said. Remarkably, no one moved.

Pacorus swelled with fury, yet the two Parthians holding the haruspex also seemed less certain.

‘The Scythians have been defeated,’ said Tarquinius. ‘That danger is gone.’

Pacorus could not stop the smirk that formed on his lips. He raised his arms in triumph, and his warriors cheered. Even the legionaries looked pleased.