The most interesting item in the room was a framed set of coins. They had been struck during the reign of Carausias, and showed the usurper’s proud profile alongside the legitimate continental emperors he had claimed as his ‘brothers’, and icons that portrayed him as a fulfilment of Virgilian prophecies of a saviour of Rome.

Volisios was still watching him uneasily.

‘So,’ Thalius said, ‘you were a supporter of Carausias?’

‘Never,’ Volisios said quickly. ‘I just collect the coins. They are already rare, and quite valuable. Just think! The coins of a British emperor. That’s all this is, Thalius, a coin collection.’

Thalius had never been one for bear-baiting. ‘Oh, you needn’t worry, man. I’m no government spy. Though I’ve no doubt you’ve plenty of murky secrets - what, a coin hoard? A few sons secreted away to evade the labour levies?’

Volisios shrugged. ‘Doesn’t everybody try to get away with a little? The taxes these days are too much to bear. And it’s all corrupt anyhow.’

‘You’re right about that,’ Thalius said grudgingly. ‘Too many are on the take. The Emperor is coming to Britain to raise troops for his war with Licinius.’ Licinius ruled the eastern half of a sundered empire. ‘But I’m hoping that while he is here he will do something to clean up our civic life.’

‘And lower these wretched taxes,’ Volisios said.

‘Oh, I doubt even the Emperor will be able to manage that,’ Thalius said dryly, and he turned back to the coin images of the doomed usurper.

Thalius remembered the rule of Carausias well; he had been in his twenties when Carausias took power. The man had commanded the British fleet, responsible for intercepting Saxon pirates as they sailed across the sea from north Germany. It turned out he was allowing the raiders through, then robbing them as they tried to return home. When the provincial government not unreasonably challenged this policy, Carausias led his troops in rebellion. For a decade he (and later his own usurper) held off the continental Tetrarchy and ruled as emperor in Britain.

It was all very exciting, and Carausias, charismatic and imaginative, had been popular. His island domain was a British Empire sustained by sea power, with a ‘Rome’ of its own at Londinium, and Thalius, rather thrilled, had wondered if this was a glimpse of the future.

But the hard truth was that for Thalius, at that time a young man assuming his own burdens as part of the curia of Camulodunum, a change of hierarchy at the top of society had made no practical difference. And the fragile rebellion had been decisively crushed when Constantius Chlorus led his massive Invasion of Britain, and reclaimed the island.