Nennius struggled to reply. ‘Surely not God - but if God has such powers, who’s to say that humans won’t be able to emulate Him some day? What if it was a man, a man or woman of our time - or even of our own future - who, through the power of prayer, reached back to meddle with the past through the Prophecy? The family legend is of a Weaver, who stands outside the tapestry of time and can pluck at the courses of our lives as if they were mere thread.’

Tarcho said, ‘And if he did, this Weaver - what was the point? Why murder Constantine?’

‘To save Christianity,’ Nennius said briskly. ‘That was clearly the meaning our grandfather and his companions extracted from the surviving acrostic. If Constantine had died then, he could not have corrupted Christianity into an arm of the state - and it would not have become as intolerant as it has. There would have been no persecution of one Christian by another, no hounding of a thinker like Pelagius.’

Tarcho nodded. ‘So Christians of the future tried to have Constantine killed, and their faith restored to a lost purity. Is that what you’re getting at?’

‘Yes,’ Nennius said. ‘Well, perhaps. I don’t know! I am reconstructing events of centuries ago, and the mysterious motives of figures behind them, without even having available the primary evidence, the Prophecy itself.’

Tarcho frowned. ‘It all sounds a bit devilish to me.’

Maria mused, ‘But if you had such power, if you could deflect history - why use it that way? The Church is surviving even where the empire isn’t - like here, in Britain. It’s like a suit of clothes worn over the body of the empire, still standing even though the skeleton within has rotted away. If I could change history, I wouldn’t worry about the Church, for the Church is robust enough to withstand the meddling of a thousand Constantines. I think I would find a way to hurry up the day when Britain returns to Rome.’

Nennius nodded sagely. ‘Of course. Britain has always been part of the Roman world. It is only a matter of time—’

Tarcho snapped, ‘No. It’s different now. Rome is the last of a line of antique empires that go back to Alexander. But the world has changed, and Rome has had its day. If the Caesars ever do come back they won’t be welcomed.’ He eyed Nennius. ‘You know, you should stay here, cousin. Here in Brigantia. Our family has been many things, soldiers, stonemasons and scholars. But at heart we have always been Brigantians.’

Nennius frowned. ‘But Aeneas of Troy came to Britain and—’