But Gnaeus laid a restraining hand on his arm, and pointed into the sky. ‘It is the sunrise, sir. He is puzzled by it.’

Remus was rising, the second star of this double system, brighter than Luna or Venus, brighter than any star in the sky of Terra. Everywhere the shadows became doubled. Romulus never shifted in the sky of this world, but Remus did, following a convoluted apparent path that even the ship’s Arab mathematicians had had difficulty puzzling out.

And a runner came dashing from the anchored cetus. ‘Centurion! There’s a report of a riot at the colonia. The men are in the granary, and are threatening to burn down the principia—’

‘What, again?’ Quintus raised his head to the sky and let out another roar. ‘Father of the Christ, why do you goad me? With me, optio.’ And he stalked off back to the cetus.

Yuri Eden watched the second sun rise, entranced.

CHAPTER 4

For lack of any clearer orders, it seemed, the troops who had followed their commander out to meet Yuri and Stef waved their short swords and ordered the two travellers to follow Quintus back to the airship. ‘No funny stuff, mind.’

Stef helped Yuri hitch the pack on his back as they followed the men, listening to their gruff speech. She murmured, ‘So they’re all speaking Latin.’

‘Or a lineal descendant of classical Latin anyhow,’ the ColU said. Reduced to its processing centre, the remains of the autonomous colonisation unit rode in Yuri’s backpack, and whispered in their ears through the plugs it had provided, projecting translations of their words at the Romans.

‘But,’ said Stef, ‘even I can tell there’s a whole bunch of accents in there.’

‘Rome always was an amalgam of many nations,’ the ColU said. ‘A forced joining. In the latter days, in the west, provincials – who had been regarded as barbarians in ages before – rose to high command in the Empire. Stilicho, for instance, the best military leader of the late Empire in western Europe.’

‘I admire your grasp of history, ColU,’ Stef murmured. ‘Among your other accomplishments.’

‘I was programmed to serve as tutor to the children of Yuri’s colony on Per Ardua. My knowledge base is broad.’

Yuri said, ‘I think she’s ribbing you.’

‘Well, I am happy to serve, even though that destiny has changed—’

‘And so,’ Stef said, ‘it appears, has the destiny of Rome. The Caesars didn’t travel to the stars. They didn’t even have airships, as far as I know. Maybe the history you remember is out of date, ColU. I wonder if these Romans ever heard of Stilicho.’

‘You are right, of course. These are not our Romans. We can be guided by our knowledge of our own history, but we must always be aware that things are different here.’

‘Here, on the other side of the Hatch,’ Yuri said.

‘The word the Romans are using for the emplacement is actually more like Gateway,’ the ColU said. ‘I have chosen to translate it to the more familiar term …’

Stef shook her head. ‘Here we are discussing a whole new history, as if it was normal. Are we all going crazy? As if it happened every day.’

The ColU said softly, ‘At least we are coping, Colonel Kalinski.’

And Yuri grinned. ‘Besides, didn’t it already happen to you once before, Stef, back on Mercury? It is – difficult, though. Do you think if we stepped back through the Hatch – if these goons in fancy dress ever let us – we would find ourselves back where we came from? I mean, on Per Ardua, and with the only Romans in the history books where they belong?’

‘Somehow I doubt it, Yuri Eden,’ the ColU said. ‘Having stepped through this door—’

‘We can never go back. If there are Romans here, they’re going to be everywhere, right?’

‘We must make the best of it, Yuri Eden. And after all, nobody forced us to come here, through the Hatch.’

Yuri looked drawn, tired, Stef thought – ill, perhaps. They had all been through a lot, this long day – even though, as a glance at her watch showed her, with shock, that not an hour had passed since they’d said their goodbyes to Liu Tao, in the middle of the chill farside of Per Ardua, planet of Proxima Centauri. It was obvious they’d travelled a hell of a long way from Proxima, itself four light years from Earth. And travelled more than mere distance – more than just light years. What was this place?

They reached the airship.

Stef was shoved none too gently by a legionary’s palm towards a rope ladder. She climbed stiffly, followed by Yuri.

The two of them – three with the ColU – were pushed into a hold at the base of the gondola, roomy but without windows, and lit by a crude-looking fluorescent lamp. They had no view out. They had no seats either; they were made to sit on the floor, with their backs to the wooden wall. The soldiers sat around on their cloaks, talking softly, and looking speculatively at Stef, who glowered back.

The ship, which the Romans called a cetus, lifted with a smooth acceleration, a hiss of bellows somewhere.

‘The walls are wooden,’ Yuri observed. ‘And the floor. I see straw, and blood stains, and the whole thing smells of sheep.’

‘And goats,’ Stef said. ‘Although that could be the legionaries. This has to be some kind of surface patrol vessel. Starship in orbit somewhere? You wonder what kind of technology they must have up there if this is the best they can do down here.’

‘If they have kernels,’ the ColU said, ‘quite crude enabling technologies may be sufficient for other purposes, such as life support. Kernels – which, incidentally, they refer to as vulcans, after the god of the forge. I have translated appropriately.’

The legionaries watched them suspiciously as they spoke, and Stef was uncomfortably aware of how eerie it might seem to these characters – bored, heavily armed soldiers – if she and Yuri appeared to be listening to a voice, even responding to it, that they couldn’t hear. It was almost a relief when one of them grunted, ‘No talking.’

Stef shrugged. But she saw that Yuri’s eyes were closed anyhow, his arms folded over the backpack on his lap, his head lolling.

It wasn’t long before the airship descended. As anchor chains rattled, the legionaries debated briefly among themselves. Then they stood, opened the door to the short corridor down which they’d come to this hold, and shoved the travellers back to the hatch through which they’d clambered aboard the vessel. There they were made to wait until Quintus Fabius and a few of his officers had gone down the ladder to the ground.

Stef ducked so she could look out of the hatch. She saw an enclosed compound, roughly rectangular, laid out over the purple-streaked ground, with walls of sod and what looked like orange-tinged wood, and central buildings of wood and thatch. Carefully she pulled a slate from her jacket pocket. ‘Hey, ColU, you might want to see this.’ She held up the slate to serve as the ColU’s vision.

‘Remarkable. Remarkable! A classic Roman legion’s marching camp. Displaced thousands of years in time, and brought across the stars …’

They were prodded down the ladder.

On the ground, the leader of the little group of soldiers delivered them back to the retinue of Quintus Fabius. Quintus ignored them, but Gnaeus Junius, the second in command – the optio, Stef learned – waved vaguely. ‘Oh, just stand over there and stay out of trouble.’

And trouble there was, as Stef could see. Shoved to the periphery, ignored as the Romans bickered among themselves, she tried to make sense of all this.

Centurion Quintus was in the middle of some kind of argument with a group of legionaries, most dressed in what Stef was coming to think of as the characteristic style of these post-Romans – much as Roman soldiers had dressed in all the history books and reconstructions she’d seen, even if they were generally drabber, dirtier and more battle-scarred. They all wore heavy belts, with loops for weapons and immense ornate buckles. The belts were the single most striking feature of their costume, she thought, gaudy, almost barbaric. Quintus dominated proceedings in his scarlet cloak and spectacularly plumed helmet.