Romulus used the silence to shuffle closer to Brennus. Side by side, they were an imposing pair: the huge Gaul with bulging muscles and his young protege, slightly smaller but just as solidly built. Although Romulus had no more than a dagger, they would account for themselves very well if it came to a fight. The pair glared at the five veterans.

Novius lowered his sword. ‘Only citizens are supposed to serve in the legions,’ he said resentfully. ‘Not tribal vermin like you two.’

‘That’s right,’ agreed Caius.

The fact that they had served in a mercenary cohort under Crassus was not mentioned. That Romulus was apparently half-Italian. Or the fact that the Forgotten Legion was not a Roman army unit, but a Parthian one.

‘That’s a different matter,’ Brennus replied smoothly. ‘Here we’re all brothers-in-arms. It’s us against the Parthians, miserable scumbags that they are.’

His words seemed to have the right effect on the veterans; they turned to go, Novius taking up the rear.

Grinning at the Gaul, Romulus began to relax. It was the wrong thing to do.

The little legionary turned at the door. Brennus gave him an evil look, but Novius stood his ground. ‘Odd,’ he said in a strange voice. ‘Very odd.’

With a sinking feeling, Romulus saw that Novius was staring at Brennus’ left calf, which had a prominent purple oval of scar tissue.

‘What is it?’ called Caius from outside the barracks.

‘Instead of branding them on the shoulder, Governor Pomptinus made us mark the captives’ calves on that campaign.’

‘I remember,’ came the response. ‘So what?’

Although he had never asked, Romulus had always wondered why Brennus’ mark was different to other slaves.

‘It was to show they were his property,’ crowed Novius.

‘Tell me something I don’t know.’ Caius sounded bored.

‘This brute has a scar just where his brand should be,’ announced Novius delightedly, lifting his sword again. ‘He’s a damn slave too!’

Before he could do more, Brennus lunged forward and shoved the little legionary in the chest. Novius flew out of the door, landing flat on his back. His four friends scattered, their faces alarmed.

‘Piss off, you son of a whore,’ the Gaul said from between clenched teeth. ‘Or I’ll kill you.’

‘Scum!’ Novius wheezed, his face twisted with rage. ‘You’re both escaped slaves.’

Romulus and Brennus did not reply.

‘Felix probably was too,’ the little legionary added as the others reached for their swords.

‘There’s only one punishment for that,’ snarled Caius.

‘Crucifixion,’ finished Optatus.

Primitivus and Ammias, their companions, raised their gladii in unison at that prospect. Five faces filled with hatred ringed the doorway.

Romulus’ stomach constricted into a knot. He had seen the brutal method of execution carried out many times. It was a slow, agonising death.

‘Just try it,’ Brennus bellowed. His temper was fully up, and he stood in the door like a raging bull. Only one man could attack him at a time. ‘Who’s first?’

None of the veterans moved. They were no fools.

Romulus pelted back to their room, scooping up his scutum and sword. There was no chance to don his chain mail, but armed like this, he felt more of a match for their new enemies. When he got to the entrance, Brennus had come back inside.

‘Bastards,’ he growled. ‘They’re gone. For now.’

‘They’ll tell everyone,’ said Romulus, struggling not to panic. The Parthian officers didn’t care about their history, but it would not be popular among the others in their century. Or, for that matter, the whole legion.

‘I know.’

‘What can we do?’

‘Not much.’ The Gaul sighed heavily. ‘Stay alert. Watch each other’s backs.’

This felt all too familiar. Neither spoke for a moment as they considered their options.

There were none. Escape was out of the question: it was deepest winter. Where would they go anyway? And Tarquinius, the one man who might be able to help, was still incarcerated with Pacorus. They were alone.

Glumly, Romulus studied the burnished iron of his gladius. He was going to be sleeping with it from now on.

It took Novius little more than an hour to tell every man in their century what had happened. He didn’t stop there. The little legionary seemed possessed as he moved between the low-roofed barrack buildings, spreading his gossip. Caius, Optatus and the others were just as busy. Informing over nine thousand men took time, but gossip travelled fast and by nightfall, Romulus felt sure that their secret was well and truly public news.

The hardest thing to take was the reaction of his comrades in the barracks. Eighty of them ate and slept cheek by jowl, sharing their equipment, food and lice. Although the unit had been formed after Carrhae, there was a real sense of camaraderie. Felix had been part of it too. Far from Rome, they only had each other.

That no longer applied to Romulus and Brennus.

Or Tarquinius.

Men tarred them all with the same brush and the altar to Aesculapius and Mithras was dismantled the same day, its offerings taken back. Who would pray for a man with slaves as friends? Yet when the legionaries had nothing to pray for, they had nothing to hope for either – so they needed something to fill the void. Unfortunately, that turned out to be distrust of the two friends.

Suddenly Romulus and Brennus were responsible for all the men’s misfortune.

Crucifixion was not that likely. To earn that punishment, Romulus or Brennus would have to fall foul of a Parthian officer. But there were countless other ways a man could be killed. Petty arguments were commonplace and with every man in the Forgotten Legion a trained soldier, they could be ended quite easily. Poisoning food, the norm in Rome, was not as popular as the use of weapons. Because men dropped their guard when in the latrines or bathhouse, being jumped in those locations was common. The narrow gaps between the rows of barracks were also dangerous places. More than once Romulus had come across bodies covered in stab wounds just a few steps from their quarters.

But the most immediate danger was where they slept. Eight men had to share a small, cramped space and when one quarter of those were being ostracised, it made life very difficult. On hearing the news, a pair of legionaries had instantly moved to another contubernium that was two short. Their disgusted faces upset Romulus hugely. That left Gordianus, a balding veteran, and three soldiers on one side of the room, the friends on the other. Gordianus, the obvious leader now, had not said much in response to Novius’ revelation.

This kept his companions quiet, for which Romulus was grateful. He could take silent resentment. While it was doubtful that any of their own contubernium would try to kill them, they could not be trusted. Like a viper sliding through the grass, Novius was forever appearing unexpectedly, muttering in men’s ears and poisoning their minds. The little legionary had taken to hanging around in the barracks corridor, idly picking his nails with his dagger. When he wasn’t there, Caius or Optatus were. While none made any overt signs of violence, it was most disconcerting. If Romulus and Brennus responded by killing any of their enemies, they would be severely punished. And there were too many of them to risk a night attack. Cutting five men’s throats quietly was an impossible task.

So Romulus and Brennus cooked together every day and stood outside the latrines with a ready sword while the other went inside. They went on sentry duty simultaneously, and only one slept at a time. It was exhausting and demoralising.

‘This is worse than the ludus,’ muttered Brennus on the second night. ‘Remember?’

Romulus nodded bitterly.

‘There we could at least bolt the door on my cell.’