To investigate, Darius hand-picked a squad of six men, including Romulus and Brennus. For reasons best known to himself, he also chose Novius and Optatus. The veterans leered at the friends as they leaned their pila against the timber wall. Javelins would be no good at close quarters. Instead they all drew their gladii. Pulling his own blade free, the stout Parthian led them inside the camp. He was totally unaware of the tension between the men behind him. There was a brief delay; no one wanted to have his enemies at his back. Then Romulus darted through the gate with Brennus, leaving the others too far away to try anything. Mouthing silent curses, Novius and Optatus followed.

The dirt beneath their feet was hard-packed from the passage of men in and out of the fortlet, so their hobnailed caligae made no sound. A deathly silence greeted them. The atmosphere within was eerie. Unnerving. Part of the garrison might be on patrol, but there should have been at least some soldiers visible.

Not one was.

Where are they? thought Romulus. Was it possible that they had abandoned the fortlet?

Apart from the observation tower, a single barracks building and a small latrine block, the only structures were an earth oven under the west wall and a number of altars to the gods positioned here and there. Large, tell-tale dark stains marked the ground, bloody proof that all was not well. There were uneasy murmurs from the others at the sight.

Hairs prickled on the back of Romulus’ neck. There was death here, its presence suddenly overpowering. He looked up, expecting to see clouds of birds of prey hanging high overhead. There weren’t many though, and those present were probably just eyeing the refuse heaps that existed outside the camp. Why were there not more?

Brennus could sense it too. Nostrils flaring, he reached up to touch the hilt of his longsword, which was hanging from his back. In open combat, it was still his favoured weapon.

‘What’s that?’ hissed Darius. They were now very near the barracks.

They froze, ears pricked.

A low sound reached them. There was no mistaking the moan of an injured man. A survivor.

Using the tip of his sword, the Parthian flipped open the flimsy door. It made a hollow sound as it banged off the wall. Inside, the floor was slick with blood. Drag marks led towards the small rooms shared by the contubernia of eight men. With only a half-century in this fort, there would be five such, and a larger chamber for the optio in command. Wrinkling his face with distaste, Darius jerked his head at Romulus, Novius and another soldier. ‘You three go left,’ he ordered. ‘We’ll go right.’ Taking Optatus and the fifth legionary, he entered.

Brennus was left outside.

Romulus gripped the bone handle of his sword tightly. Jupiter, Greatest and Best, he thought, protect me. The narrow corridor echoed to the sound of their caligae as Romulus led the way, with the others one step behind. All held their shields high, their gladii ready. He was acutely aware of Novius at his unprotected back.

‘Don’t worry, slave,’ hissed the veteran. ‘I want to see your face as you die.’

Romulus spun round, glaring. He longed to end the vendetta right then.

‘Found anything?’ bellowed Darius in an odd voice.

The question broke the spell.

‘Not yet, sir,’ Romulus answered, turning back. His voice died in his throat as he reached the first chamber.

There was no need to worry about being attacked. Each room was exactly the same. Their limbs at awkward angles, mangled corpses lay heaped untidily on top of each other. All the legionaries had been stripped naked, their mail shirts and faded russet tunics discarded on the floor alongside. Clotted blood lay in great pools around the still bodies and mounds of clothing.

Even Novius looked disgusted. ‘Who does this to an enemy?’

‘Scythians,’ Romulus said calmly. Tarquinius had told him about their barbaric customs.

‘Fucking savages.’

Every body was mutilated in the same manner: beheaded as well as partially skinned. Patches of skin were missing from chests, backs and legs, and there was no sign of the soldiers’ heads. Romulus knew why. According to Tarquinius, the Scythians measured a warrior’s courage by the number of heads he carried back from battle. They also used the tops of enemy skulls as drinking vessels, covering them in leather and even gilding them inside, while skins were used as drying cloths and scalps as decorative handkerchiefs on their horses’ bridles. Revulsion filled Romulus at this level of savagery. Breathing through his mouth, he realised that he could smell very little. Even though these men had clearly been dead for more than a day, the bitter cold had prevented much decay.

‘Why did they carry them inside?’ asked Novius.

Romulus looked at him with scorn. The answer was obvious.

Realisation hit the veteran. ‘So there would be no cloud of vultures overhead.’

He nodded.

Suddenly there was more at stake than their feud.

As one, they turned and ran in search of Darius. They had marched into a trap. Now it was surely about to be sprung.

The trio found their commander on his knees in the optio’s quarters. He glanced up as they entered, his face twisted with fury. The junior officer lying cradled in his arms had not been treated in quite the same way as the others. Remarkably, he was still alive. A strong man in his thirties, the optio had been scalped and entirely flayed. Barely conscious, uncontrollable shivers shook his bloody, ruined frame. He did not have long.

‘Sir,’ Romulus began.

‘They posed as a trading party. Got inside the gates and then produced hidden weapons,’ snarled Darius. ‘Dirty Scythian dogs.’

That made sense, thought Romulus. But there was no time to waste. ‘Sir. They hid the men in here so that the vultures would not warn us off.’

‘Of course,’ gasped the Parthian. ‘And we just walked in, like complete fools.’

‘Best get outside, sir,’ said Novius, his muscles twitching with impatience.

Darius nodded briskly. ‘And this poor creature?’

‘Give him a warrior’s death,’ said Novius.

Rather than let the mortally wounded die in pain, Roman soldiers always performed a final act of mercy.

‘I’ll do it, sir.’ Romulus’ voice echoed loudly in the confined space. Novius and Optatus began to protest. Slaves could not perform this duty.

But a warning look from Darius quelled their objections. ‘This man volunteered first,’ he said, thinking they also wanted the honour. ‘Outside.’

The malevolent legionaries had no choice but to obey. Saluting resentfully, they left, followed by the other two soldiers.

‘Do it quickly.’ Laying the maimed optio down with care, Darius passed his hand over his forehead in a blessing and strode from the room.

Lifting his gladius, Romulus stepped closer. It was right that this death should be his. Darius was not Roman, while Novius and Optatus were evil men who should end no one’s life. The last two had not volunteered, so it was up to him to give the optio a dignified passage to the other side.

The man’s eyelids opened and their gaze met. Both knew what was about to happen.

Admiration filled Romulus. He could see no fear in the optio’s face, just calm acceptance.

‘Sir,’ he said. ‘Elysium awaits.’ Brave men went to the warrior’s paradise.

There was a single nod.

Gently Romulus helped the other to sit up. There was an involuntary gasp, rapidly concealed. Even a small movement must be agonising, he thought. Pity filled him.

‘My name is Aesius. Optio in the Second Century, First Cohort, Twentieth Legion,’ managed the injured officer. He looked round enquiringly. ‘And your name?’

‘Romulus, sir.’

Aesius’ twisted face relaxed. ‘A man should know who sends him to heaven.’